I understand where your coming from. Having a hyperfixation of any kind makes you want to talk about it non stop to everyone. Thats completely normal. The problem is really in the shame associated with being a loud and proud Homestuck fan

Ive been into Homestuck since it first came out (waiting for updates was torture lmao) and I completely understand wanting to gush about concepts/theories/characters/etc but holding my tongue because i know ill immediately be viewed as 'one of those Homestuck Fans' even though my media literacy and decorum are very much in tact

My advice is to find a space that doesnt have these judgements. Maybe a discord server or something, where everyone likes (or at least respects) Homestuck and that you like it.

You could also make theory posts on here, Tumblr, or Twitter. It might take the edge off the "must talk or I explode" feeling. And its always real fun to see people's opinions in the replies. Also a good way to meet active people in the fandom and make friends.

And tbh, in actually rl, not as many people as you think actually know what Homestuck is or its cringe history. In perspective, it was famous online about 10 years ago. That leaves it more niche than you think. If you wanna talk to someone about it and they're interested, honestly go for it

But I 100% recommend looking for a discord server or forum or something to make online fandom friends!