Some sort of curated tags or community tags might also be nice.
But this will probably not fly, because of lack of participants. Games struggle to get comments and reviews, so such tags would be prone to heavy bias, or even trolling, for the smaller games.
As it is now, there is of course very heavy bias, beause the developer choses what tags are relevant and what genre a game is. A game on Steam has more than 20 tags, and we only see the most relevant 20 tags chosen by user majority vote from a limited pool - as far as I understand the system. On Itch it is 1 genre and up to 10 tags. Freestyle tags. Chances are you disagree with half the tags of most games. Or at least think that other tags would be more relevant.
I sometimes wonder if the lack of tag accuracy is contributing to the low priority of tag exclusion. Filtering out "horror" will not filter out "psychological horror" or "creepy". And from the other side, just because the dev tagged it horror, does not mean you would call it a horror game.