I was delighexcited to do them!,

“Delighted” sounds too formal for this context.

Bbut I was so tired.

Match capitalization with previous correction. Conjunctions at the beginning of the sentence are generally not preferred and in this case it makes the most sense to combine this with the previous sentence using a comma.

In tThis evening I also came up with the names of recipes that I'll film tomorrow.

Words like today, tomorrow, this morning, tonight, etc. don’t have prepositions attached.
Ex.
I'm going to a party tonight. ✅
I'm going to a party at tonight. ❌
I'm going to a party in tonight.❌
I'm going to a party on tonight.❌
You can use “at” for specific times (eg. At 3 pm), “in” to talk about how far away a time is from the present (eg. He's coming back home in 2 weeks), or “on” to talk about a specific, absolute date (eg. I will not be home on November 3rd).

Names of recipes - unless you're naming all of your recipes the same thing, you are referring to multiple names in this sentence and need to use the plural.

After I post my journal ion the langcorrect.,

The word “after” makes this a dependent clause - it can't exist by itself because it's not a complete thought. You have to combine it with an independent clause to make it a full, grammatically correct sentence.
Ex.
While I do my homework. ❌ (not a full thought! What is happening while you complete your homework?)
I eat snacks while I complete my homework. ✅ (best)
While I complete my homework, I eat snacks. ✅ (correct but awkward)

When talking about posting online, you either post “on” or “to” a site, not “in”.

Lang correct is a website and therefore a proper noun. You can't precede it with articles (like “the” or “a”).
Ex.
I posted on Lang correct this morning. ✅
I posted on the Lang correct this morning. ❌

Ii'll sleep.

Match capitalization with previous correction

I was delighted to do them!, but it was very tiring.

I think that you can combine these two sentences to make it sound better.

But I was so tired.

In this eveningTonight I also came up with the name of recipes that I'll film tomorrow.

After post my journal in the langcorrect, I'll sleep.

I'll sleep.

In tThis evening I also came up with the names of the recipes that I'll film tomorrow.

or,

Tonight I also came up with the names of the recipes that I'll film tomorrow.

After I post my journal in the langcorrectentry to Langcorrect, I'll go to sleep.

or,

After I post to my journal in Langcorrect, I'll go to sleep.

I'll sleep.

I was delighted to dofilm them!

You wouldn't "do" the recipes, but you might film them, make them, cook them

In tThis evening I also came up with the name of recipes that I'll film tomorrow.

In the evening = referring to evening in general
This evening = this specific evening

After I post my journal in theon langcorrect.

You would make a post "on" langcorrect, Facebook, etc