I had a friend like this, but he had a lot of mental diagnoses, and idk which one was causing it, I think he stopped after BPD or schizophrenia medicine was readjusted for him. I'm not saying it's the case for you, of course.

nobody wants to read your 20,000 word essay on why their favourite game is dogshit

I actually hate seeing people liking shit games, e.g. Dragon Age Inquisition, and people writing long critiques of such shit is what keeps me alive.

It is hard to respond to walls of text, I won't lie, but I have ADHD and I blame it on it.

I feel like you'd fit right in into my childhood hobby of online forum roleplays. I remember when posts initially were brief descriptions of events and eventually the minimum standard turned into two A4 pages per post. If you never heard of it, you can try to find something up your alley in the I reckon most popular directory here: http://rpg-directory.com/index.php?c=4 I haven't interacted with the hobby in so. many. years. I've no clue what the culture and activity is like nowadays, but I think it would give you the space where your long posts are welcomed and sought for.

I'd also recommend avoiding Discord. Welcoming Discord communities are very rare. It's mostly cliques who won't accept you even if you act like a normie.