For a few years I've made it a personal point not to read any political coverage with overblown action verbs in the title like "X slams Y over spending bill" or "Y attacks Z". It's subjective but I swear it has genuinely helped my mental health. A filter that does this would definitely be nice now that you mention it!

You can block the whole Fediverse community. I did. Like, it's helpful. I also blocked asklemmy. Also helpful. I haven't blocked it on kbin, though. It doesn't matter, I see shit I'm not subscribed to when I filter by "subscribed" still. I think filtering by keyword is going to be a long time away. You can be obnoxious as a commenter, though. When you see the keyword, say something contrary in a comment. That could be fun.

It will be so important once US election cycle comes around. It became a game of wack a mole individually blocking subreddits versus just setting relevant keywords to make the reddit viewing experience wonderful as opposed to a rage inducing. We need a Fediverse Enhancement Suite.