There is a negated tag for ai search. https://itch.io/games/tag-no-ai
It will display all games where the ai disclosure question was answered. Mind you, the ai disclosure question is only mandatory for assets. And for games, it would catch a lot of games, that just used ai assisted coding tools. That tag does not differentiate between the different ai categories. There are positve ai tags for images, sound, text and coding, but the negative tag is only a catch it all.
The AI infos are not implemented well yet. And the grace period for assets is still going on. https://itch.io/t/4309690/generative-ai-disclosure-tagging
I thought I read a hint a while back about the search or browse to be changed somehow. But no specifics, and I guess other matters got in the way, so it was delayed anyway.
For filtering, I belive that individual filtering of games is superior to "large scale" filters. If you go look for games you like, you are bound to see the games you already know very often. Imagine clicking them away, not be be seen again, except in your library. Even though I made a small gui button for that exclude filter and even a genre filter, the only thing I ever use for filtering is that individual filtering method.
Now, if Itch would have the tags on the browse page, like they have some tags on the itch.io page, doing a tag filter client side would be trivial. (That genre filter I mentioned works this way, since the main genre actually is shown.)