Don't get me wrong, my server also runs a ton of crap, like git/email/backups/irc/mysql/etc. plus a couple websites and some python scripts (3x doing continuous data logging, 2x providing some service), but it draws less than a traditional light bulb and also runs everything in linux containers. Unless you're doing large data processing tasks like machine learning on a weekly/daily basis, odds are you don't need more than two consumer-grade cores (I've got more since I repurposed an old laptop, but they're very rarely used). Large RAM is nice, though, I do have to say that. My 8GB is stretching it a little, considering that my favorite email server software is a Windows GUI thing and so I run virtualbox to have this guilty pleasure, which consumes about a quarter of the system's RAM just for one service.
Aside from Owncast, no idea what requirements that has, I think all of OP's services would be fine with a Raspberry Pi as well, just RAM would be tight with so many individual containers. Especially given the static site hosting, and doubly especially with that offloaded to a CDN, the only dynamic things (screenshot hoster, pastebin) are own use and won't see a dozen concurrent users continuously or anything.
Edit: I read over the -track API websites part. I don't know whether those might fit on a Pi as well, but that sounds like various people make use of it and this server is not just single user.