Well, if you do search for tags, the most popular ones should not be dead projects. Hopefully. And if you do search for something and the top results do include certain tags very often, maybe that is, what you really want, but might not call by that name. Also, there is no general guideline what to tag. No cheat sheet, to go step by step to select from a fixed pool of tags. The tag pool is not even fixed.
So for example, if you do want to filter out AI generated content, this depends on the developer using the same tag as you would. Also, some might even use techniques they would call AI, but you would not. Oh, and many devs do not tag this at all. Why should they? Technical aspects can be tagged, but tags are limited and tagging what the game is about is more important than tagging how the game was made. There are some hidden "tags" for game engines and such. Directory at the bottom of the page has some of those. It is certain meta-info that is also searchable by something akin to a tag. And I have no idea where a page with these links is. They are handy for that: https://itch.io/game-development/engines So you will have games with https://itch.io/games/made-with-twine and games with https://itch.io/games/tag-twine (and those lists are not the same).
There is work done on the search features, but what is on the roadmap or when it arrives was not told, as far as I know.
There is one "undocumented" way of filtering out one (1) tag. Make a bookmark with your tag search and add "?exclude=tg.xyz" without the quotes and change xyz to the tag, as seen in the url, with - and all. (This only works if you are logged into your account .)
If you are on pc and willing to do things client side with addons, you can do a little more. I made a button for that feature above, another thing to filter the main genre and a thingy that do can filter out developers (or individual games).
You can also do your own filtering with a user style addon, but it is a hassle to manage the css filters. It is someting like this
@-moz-document url-prefix("https://itch.io/games") {
div.game_cell:has(a[href*="//username1.itch"] ) { display: none !important }
div.game_cell:has(a[href="https://username1.itch.io/game1"] ) { display: none !important }
}