I don't want to come off all self-righteous as in "PieFed has that already"... but OTOH it's relevant that, yeah, PieFed has something for that already.😄 It is described at https://join.piefed.social/2024/06/22/piefed-features-for-growing-healthy-communities/, and I think its way too sensitive atm, labeling users of comics in particular as potentially troublesome bc they post more than comment, but anyway it seems relevant here as an attempt to do what you are saying: to allow for some measure of an account's "reputation" across the Fediverse, similar to what those aforementioned communities do irt mods to let people know about stuff that they may find pertinent as they make decisions about what to do about it - like not post to certain communities and instead help others grow. In short it's a tool that helps shorten the learning curve rather than make each person have to do all that work all entirely on their own.
So someone downvotes twice as often as they upvote?
Someone has twice as many heavily-downvoted comments as positive or neutral? Also a paddling. It also helps provide additional choices beyond merely a moderator's power to "remove vs. allow" - one day a user could perhaps make their own thresholds, or like automatically collapse (to deemphasize, but while still retaining) a comment from such a user. Or not - I have some of that turned OFF at PieFed, but it's awesome that it's there if someone were to want that.
Someone has a brand-new account merely hours old? That's NOT a paddling, but it is worth its own unique icon to let recipients know that they are dealing with a newborn (ofc they could be an alt) who may not realize how the Fediverse works.