> My feed is almost entirely filled with people who use Twitter as something like Deviantart or Pixiv to upload original artwork and only use the character count for writing a description or title

Me too! If I discover an artist I like, I'll scroll through their feed quickly before I decide to follow. If they tweet mostly one liners or politics with only the occasional artwork, then it's a pass from me.

One other thing I'd suggest is muting certain keywords. Adding political terms to your mute list can clean things up significantly.