I have trouble with your concept. Finding "hidden gems" is all good and nice on paper.
But how would that even work? You need curation work here. Big time. Adding games by whatever tagging mechanisms might in theory connect games to players according to interests. But this means, you have to do better classification than the platforms you pull the data from. The data from Itch is garbage in that regard. Tags will not capture what the game is. You need crossreferences to a player profile, to get a handle on what the game resonates with.
This would be possible with massive curation work. In other words, objective reviews that can be split into those "vibes" and are not just a number like 4/5.
And I do not think there are many hidden gems in the 1.2 million games on Itch that do not even have a single rating, negative or positive.