Text of/for today.

Today I'm gonna write a short text because I'm not pretty sure of a concrete topic to write about.

At this moment I'm watching some Youtube's videos about personal growth, law of attraction, etc.

Today, after almost one month, iI'll go to the gym, that. It's a new gym in my neighborhood, and it is close to me, it is 5 minutes walking distance from my house.

Most of the things you separated with commas can exist as their own sentences, so I changed it to make it flow better

Text of today.

It’s more natural to say, “Text for today”

Today I'm gonna write a short text because I'm not pretty sur don’t have a concrete topic to write about.

You could also say, “I’m not sure what to write about.”

At this moment I'm watching some Youtube's videos about personal growth, laws of attraction, etc.

“some” is optional

Today, after almost one month, i'll go to the gym, that. It’s a new gym in my neighborhood, i. It is close to me, i. It is 5a five minutes walking from my house.

You could replace the last 3 sentences I wrote with, “ It’s a new gym that’s a five minute walk from my house.

The Text of tToday.

I tried to keep your original title, but I would suggest adding "The".

Today, I'm gonna write a short text because I'm not prettally sure of a concrete topic to write about.

Really would be a better word to use here instead of pretty. This sounds more natural.

At this moment, I'm watching some Youtube's videos about personal growth, law of attraction, etc.

Today, after almost one month, iI'll go to the gym, that's a new gym in my neighborhood, i. It is close to me, it and is a 5 minutes walking from my house.

Text ofor today.

"Today's text" would be even better, depending on what tone you want.

Today, I'm gonna write a short text because I'm not pretty sure of a concrete topic to write about.

If you were writing formally, you would say, "Today, I'm going to write a short text because I'm lacking a concrete topic." But yours is perfectly understandable and fine for casual writing, just breaking some grammar rules.

At this moment, I'm watching some Youtube's videos about personal growth, the law of attraction, etc.

"At this moment" implies you're watching them while you write. If that's not the intention, you should say, "Recently, I've been watching..."

Today, after almost one month, iI'll go to the gym, t. That's a new gym in my neighborhood, i. It is close to me,; it is a 5 minutes walking from my house.