I've finally discovered an artist of a music genre that I don't know the name of.

1. You used the past perfect tense here, in this tense you put “I have” before a verb and then said verb has “ed” added at the end of it. This is how we get “I’ve discovered”.
2. I understood what you meant with that last part, but we would normally put “of” at the end. It sounds more natural.

The artist’s name is "Starjunk 95", and the kind of music I'm talking about it's like as a kind sub genre of house music.

1. While “the artist is ___” works, “The artist’s name is ___” sounds more natural.
2. The way “it’s like” is placed in the sentence looks really unnatural. “Is a kind of” fits better.
3. Sub genre is not a whole word

I knewfound this kind of music through the video game " Neon withe", and I really liked it.

1. The verb “knew” does not work here. “Found” fits better.

The music group encharged ofmade music for the video game OST was, Machine girl, although I didn't really like themir songs, only the "style" of the soundtrack.

1. I’m not entirely sure what you meant here, but I’m gonna assume that you meant that they made music for the game, so you’d write it as so.
2. You used the word “them” instead of “their”. Them refers to a group of people or can be used as a gender neutral version of he/she, while their is a possessive pronoun used to describe something belonging to multiple people or someone we do not know the gender of or someone who decides to use gender neutral pronouns (they/them/their)

I know this could be hard to understand, but what I really loved about the video game OST was what it makes me feeling.

Now, I’ve founded this artist, who through hise songs makes me feel exactly the same thatas when I was playing the video game.

1. “Founded” is not any form of the word “find”. Founded is actually a past-form an entirely different word: “found”. This basically means to set up/establish, usually referring to a business or town.
2. I’m not quite sure how to explain that last part, it’s quite complicated and a very complex sentence, but that’s how you would write it.

(Apart from the text, I didn't know if was better to use "OST" or "soundtrack".

Please correct me.)

Both work just fine :) OST is an abbreviation of the words “original soundtrack” so it’s basically the same thing.

I've finally discovered an artist of a music genre thatof which I don't know the name.

The artist is "Starjunk 95", and the kind of music I'm talking about it's like a subgenre of house music.

I knew this kind of music through the video game " Neon wWhithe", and I really liked it.

The music group enin charged of the video game OST was Machine gGirl, althoughbut I didn't really like themir songs, only the "style" of the soundtrack.

"Video game OST" works, though I would probably say "game's soundtrack".

Alternatively: "...but I didn't really like their songs, just the "style" of the soundtrack."

I know this couldmight be hard to understand, but what I really loved about the video game OST was whahow it makesde me feeling.

Now, I've founded this artist, who, through his songs, makes me feel exactly the same thatway I did when I was playing the video game.

It is known we are talking about a "video game", so we can leave out the "video" most of the time.

(Apart from the text, I didn't know if it was better to use "OST" or "soundtrack".

I've finally discovered an artist of a music genre thatwhose name I don't know the name.

* can't end a sentence in "of" because it's a preposition, but this is more formal. Casually, or when speaking, it's fine.

The artist is "Starjunk 95"," and the kind of music I'm talking about it's like a subgenre of house music.

punctuation always goes in quotation marks

I knew this kind of music through the video game " Neon withe"," and I really liked it.

The music group enin charged of the video game OST was Machine gGirl, although I didn't really like themir songs, only the "style" of the soundtrack.

"playlist" works better

I know this could be hard to understand, but what I really loved about the video game OSTplaylist was what makesit made me feeling.

Now, I founded this artist, who through hise songs makes me feel exactly the same thatas when I was playing the video game.

I've finally discover an artist of a music genre that I don't know the name of.

The artist is "Starjunk 95", and the kind of music I'm talking about it's like a subgenre of house music.

I knew this kind of music through the video game " Neon withe", and I really liked it.

The music group enin charged of the video game OST was Machine girl, although I didn't really like thosem songs, only the "style" of the soundtrack.

I know this could be hard to understand, but what I really loved about the video game OST was what it makes me feeling.

Now, I founded this artist, who through his songs makes me feel exactly the same thatway like when I was playing the video game.

(Apart from the text, I didn't know if it was better to use "OST" or "soundtrack".