You can save a bookmark with the tag exclusion in question. Or several. The feature is not coming soon, if ever, it seems. (Button on page to do it, or *gasp* multiple exclusion.) The exclusion does not stay, if you add tags. If you always search the same combo, you can do a bookmark for that.
Using personal recommendation and similar games does help a bit to find stuff you like. I do not use the browse feature much, because frankly, the tagging is just not accurate. I rather search for a key word directly. Games are tagged by devs and they have different opinion what their game is about or what tags are relevant, or, what the tag actually means.
?exclude=tg.horror https://itch.io/games?exclude=tg.horror https://itch.io/games/tag-singleplayer?exclude=tg.horror https://itch.io/games/genre-action/genre-adventure/tag-first-person?exclude=tg.horror https://itch.io/games?exclude=tg.visual-novel