I agree it’s a complex issue, and maybe I bit off a bit more than I could chew with that segment - I will accept that.
To answer your question however: assuming I had the knowhow and the means, I think I would take a note from Steam’s playbook. The tag system is already a well-established and well-known system here on itch, and the front page already uses it to give users personalized recommendations. I’d expand the tagging options and make them more robust, and sharpen the personalization methods.
I wouldn’t get rid of the “most popular” page so much as I would make the “games for you” page a default option. Give the people more of what they love alongside some products mildly outside of the users’ niche to prevent an echo chamber and keep people open for more things. If that user follows other creators we can factor in their reviews in as well.
I’m not vain or pretentious enough to claim this is what itch should do. This is obviously not a perfect solution, and it has its own share of problems. For one, it leads to “tag wars” as everyone tries to mix and match the various metadata elements to get the most page views and clicks and hit that discovery sweet spot. Personalization algorithms also have a bad habit of digging people deeper and deeper into their per-established “rabbit holes”. But itch is not as competitive as Steam, not by a long shot, and it may (or may not) solve the issue of perceived monotony and sameness.