I've been a little frustrated lately due to my limited/poor (pick one of the two) English production skills.

I agree with Paolo12 about "writing skills. (or [...] my ability to produce content in English.)" as a suggestion to replace "English production skills" since Paolo12 is more specific. You could add an adjective like I suggested just to be explicit that you're frustrated with your level in English.

I'm still having to think too much when I write something and go back to correct myself many times.

Alternatively, "I still overthink when I write something"

The only time I use English as ato communication toole is when I exchange messages with a friend of mine who is also learning English.

We've been doing this sincefor half of this yeara year/(or you can say 6 months) and It's kind of fun.

Like Pandas62 said, since is used to indicate when a period of time started.

Even though we make a lot of mistakes, we still can understand each other and even make jokes and puns since we speak the same mother latonguage.

I should practice more the "quantity" factor as I didand immerse more like when I was lejust starnting to understandlearn theis language.

I agree with Pandas62.

It looks like simplemall and smallimple sentences are more natural than one long and complex sentence.

Sometimes, I don't know what to talk or write about so I start to procrastinate and be lazy to find any good idea ofon deciding a good topic.

But yeah, maybe English is not sticking to my production skills just because it's not too importantMaybe my English writing and speaking skills are not improving because I don't value them as much rather than listening and reading, which I doskills that I use practically every day.

However, having no deep justifications on why I want to achieve this goal could also be a potential reason of my slow progress.

I've been a little frustrated lately due to my English production skills.writing skills. (or [...] my ability to produce content in English.)

We've been doing this since half of thisfor half a year already, and it's kind of fun. (or [...] for the past half year, and Iit's kind of fun.)

I should practice more the "quantity" factor more as I did when I was learning to understand the language.

Most part of theat time was all about quantity offocused on the quantity at which I consumed content, and the urge to understand what was happening on the videos I was watching or on the games I was playing in English.

It's funny because the things I most struggle towith are the basic ones.

I'm not sure if I should practice simpler sentences or just trying to say whatever I want to say by any means.

Sometimes, I don't know what to talk or write about so I start to procrastinate and be lazy to find anycome timid in finding a good idea ofr topic.

But yeah, maybe my English is not sticking to my production skills just because it's not too important rather thanoutputting skills aren't improving because I don't place as much importance on them as listening and reading, which I do practically every day.

However, having no deep justifications on why I want to achieve this goal could also be a potential reason of my slow progress.

I'm still having to think too much when I write something and I go back to correct myself many timesa lot.

This is all optional:

Changing “when I write something” to “when writing” is completely optional.

Adding in “I” is also optional. It kind of just separates the idea of you going back to correct yourself a lot from the rest of the sentence, so you can decide based on exactly how you want the sentence to sound.

Changing “many times” to “a lot” is also optional. “A lot” is more casual.

I'm almost surecertain that this happens because I'm not practicing enough.

OPTIONAL:
You can say “I’m almost certain” or “I think” as well as “I’m almost sure”. I think “I’m almost sure” is a little less commonly heard though. I think “I’m pretty sure” or “I’m sure” would be more common examples using the word “sure”. Out of all those examples, I think “I’m almost certain” would be the most formal, while the others are used a lot more casually. “I’m pretty sure” would definitely be he most casual example.

We've been doing this since half of for six monthis year and Iit's kind of fun.

When using “since” with time, you would say a more specific time (e.g. since the beginning of the 21st century, since the invention of the computer, since April this year). If you’re talking about a
time period though, you would say “for” (e.g. for two years, for 6 months, for a week).

Even though we make a lot of mistakes, we can still can understand each other and even make jokes and puns since we speak the same mother language.

This is kind of optional.
With some adverbs, there’s a slight difference in meaning depending on their placement.
To me, “still can” puts more of an emphasis on the time, so it’s kind of like saying right now you understand each other, just as you did in the past.
“Can still” feels more like you’re saying that despite the mistakes, you’re able to understand each other anyway, which feels more applicable here.

I should practice more the "quantity" factor more as I did when I was learning to understand the language.

It sounds more natural to say “practice (something) more”.

Most part of the time was all about the quantity of consumed content and the urge to understand what was happening oin the videos I was watching or oin the games I was playing in English.

You would say “most of the time” or “majority of the time”. You could also say “the better half of that time” (you could also replace “that time” with something more specific, but that would make this sentence a lot longer). In this phrase, “better” would be referring to the longer part of that time, opposed to the part of that time that was more enjoyable or better in some other aspect.

I think adding “the” makes it more specific, so it would be the better choice here since you’re kind of talking about a specific time or event.

“On” would be if there was something physically on the videos and games, but since those are talking more about concepts, you can’t really use “on”. However, since they are shown on a screen, you could add in “on the screen” after “happening” (although that isn’t really necessary).

I was also thinking about writing more lines oflonger texts on this website, but I don't know if it's a good idea.

Your original phrasing with “more lines of text” wasn’t necessarily wrong, but it sounds very unnatural. “Longer texts” would be more natural, and would get the same message across since longer texts have more lines.

You also should technically add in a comma before “but” since it’s connecting two independent clauses, but I will admit that I’m probably guilty of forgetting to do that sometimes.

It would be overwhelming tofor people to correct long texts, and I don't want to be a burden to anyone.

It sounds more natural to say “for”, although I’m not sure if there’s an actual explanation for this or what that explanation would be.

Putting the comma before “and” follows the same rule as putting one before “but”.

You need a comma before them if they connect two independent clauses. If they connect an independent clause with a dependent clause, the comma isn’t needed. So it’s really a matter of thinking and checking if the clause would make sense as its own sentence until you get more comfortable with the language.

Maybe writing two medium-sized texts instead of one massive block of text shwould be more effective.

“Medium-sized” makes it an adjective, which is needed before “texts”. However, since when they are spoken they sound very similar, it’s a lot easier to miss this detail than it is with other words.

“Should” is kind of like a variation of “have to”, but used for talking about the future or theoretical situations.
“Would” is a variation (similar to “should”) of “will”, which is a lower modality (or in simpler terms, weaker) word than “should” or “have to”.

Since you’re only suggesting that that will be the case, not saying that it definitely will be, you would use “would” instead of “should”.

It's funny because the things I most struggle tomost with are the basic ones.

Using “most” after “struggle” is a lot more common and I think more natural sounding.

You would replace “to” with “with”, or alternatively you could also say “to do” if you also put a verb (action) in afterwards.

You could also say “struggle with most”.

I'm not sure if I should practice simpler sentences or just trying to say whatever I want to say by any means.

This isn’t an explanation of how it works, but something that you can try to remember:
Keep all the verb forms consistent. “Practice” and “try(ing)” here should be in the same form, since, in its extended form, you’re saying “I’m not sure if I should practice simpler questions or should just try to say whatever I want to say by any means”, meaning that “should” applies to both “practice” and “try(ing)”.

“Practice” is correct, partially because it’s also the shortest possible version (you could also say “should be practicing”, in which case “trying” would be ok), which tends to mean it’s the more natural of two variations (what I mean is, if you’re deciding between two concepts that are both completely correct, the shorter of the two will often be the more natural one as well. Usually, if the longer one is more natural, then it’s likely that the shorter one is incorrect in some way).

Since “practice” is correct, “trying” should be changed to “try”.

The reason why I said “try(ing)” in the explanations is to make it clear that I was talking about where you said “trying”, even though “try” is the correct option.

It looks like simple and smallhort, simple sentences are more natural than one long and complex sentence.

This is correct. The other person said “ones” and “sentences”, but that would only be used if you hadn’t already said “one”.
Basically the correct options would be:
“More natural than one long and complex sentence”
“More natural than long and complex ones”
“More natural than long and complex sentences”.

You could also say “more natural than one long and complex one”, but sounds very unnatural because of the repetition. You could say “more natural than a long and complex one”, where “one” is replaced with “a”.

I would also like to point out that making the “long and complex” part describe a plural would change the meaning slightly.

The plural would be used if you’re talking in a more general sense, and talking about them all as a whole, in which case you would also be about the “short, simple sentences” as a whole, even though you can’t make that clear since they’re already plural.

The singular, which is what you had originally, would be used if you’re talking more about a specific situation. As in, with one long and complex sentence, the version that is separated into short and simple sentences is more natural.


In terms of the changes with “simple and small”:
“Small” —> “short”, because typically when talking about length, “short” is preferred over “small”.

Then more optionally, I prefer how “short and simple” sounds.

It’s also easy to just get rid of “and” here and replace it with a comma, since both of those words are describing the same thing (sentences).

Sometimes, I don't know what to talk or write about so I start to procrastinateing and being too lazy to find any good idea of topictopic ideas.

I prefer how “procrastinating” and “being” sounds more natural than “to procrastinate” and “be”. I think this is mainly because the “be” sort of complicates it, because if you say “to procrastinate” then you would also say “to be”, but it’s very rare to find “to be” being used naturally. Usually, “being” would be used instead, so then you would also change it to “procrastinating”.

I like how “too lazy to find” sounds more. This suggests that your laziness prevents you from finding good topic ideas though, so you can decide depending on if that meaning sounds accurate.

“Any” should typically be followed by a plural (“good ideaS”) in good English, although in really casual and conversational situations you might find it followed by a singular noun.

You would say “good idea(s) for a topic” instead of “good idea(s) of topic”. However, that can easily be shortened to “good topic idea(s)”.

But yeah, maybe English is not sticking to my production skillsAnyway, maybe my production skills in English are not as strong just because it'sthey’re not tooas important rather thanas listening and reading, which I do practically every day.

“But yeah” isn’t wrong, but it feels more like something you’d say in a conversation that has gone very off topic, but you want to bring it back to the original discussion and agree with whatever point was raised. “Anyway” or “but anyway” might be a better choice here.

I’m not 100% sure what you meant by that first part with English not sticking to your production skills.

It would sound more natural to say “compared to” instead of “rather than”.
“Too (adjective) compared to” sounds better as “as (adjective) as”. (The (adjective) here is “important”)

I just wanted to prove to myself that I could learn to speak or write fluently in another language.

If you wanted to prove yourself to others (or show others) that you could do that though, you would say “prove to others that I could…”.

Since you’re talking about a specific thing which also says “I”, you don’t need “myself” unless you’re proving it to yourself.

However, having no deep justifications on why I want to achieve this goal could also be a potential reason ofor my slow progress.

You would usually (if not always) say “reason for…” instead of “reason of…”.

You would also want to do something (emphasis on the “to do” after “want”, meaning that you would say “want to…”).

I've been a little frustrated lately due tobecause of my English production skills.

As written you're sentence was totally correct, but "due to" is a bit more formal than the tone of the rest of your text.

We've been doing this since half of for six monthis year and Iit's kind of fun.

I should practice more the "quantity" factor as I did when I was learning to understand the language.

Or, "I should focus more on the quantity factor as I did..."

Most part of the time was all about the quantity of consumed content and the urge to understand what was happening on the videos I was watching or oin the games I was playing in English.

I was also thinking about writing more lines of text on this website, but I don't know if it's a good idea.

It would be overwhelming tofor people to correct long texts, and I don't want to be a burden to anyone.

Maybe writing two medium-sized texts instead of one massive block of text shwould be more effective.

It's funny, because the things I most struggle with mosto are the basic ones.

You can also say "I struggle most with", but I think "I struggle with most" sounds more conversational, which I think matches the tone of the rest of your text.

I'm not sure if I should practice simpler sentences or just trying to say whatever I want to say by any means.

It looks like simple and small sentences are more natural than one long and complex sentenceones.

I think "ones" is more natural. If you want to keep the word "sentence" at the end, it should be plural.

Sometimes, I don't know what to talk or write about so I start to procrastinate and be lazy abouto finding any good idea ofor a topic.

But yeah, maybe English is not sticking to my production skills just because it's not too important rather than listening and reading, which I do practically every day.

I'm not 100% sure what you're trying to say here. Maybe,
"But yeah, maybe I'm having a hard time with my English production skills because I'm not prioritizing them, unlike listening and reading, which I do practically every day."