I don't know why you need to delete the games from Itch, they can sit on the site indefinitely without bothering anybody, right? they're not going anywhere. People who've never heard of Happiness can discover the series anytime in the future and it only means more people will be able to see the beautiful world you've created. I myself didn't discovered it until this year, imagine I just downloaded for a short play and deleted planning to download when I felt like playing again - thankfully I got a habit to download permanently things I want to keep.
This reminds me of other things I saved or lost when they disappeared forever, like RWBY (saved ONLY because I wanted an old-fashioned Season 1-3 movie DVD), my father's music reel tapes (from 30 years ago, lost, I never took care of sensitive things), or the comment section from a music video which was so beautiful I kept it secret to keep it away from trolls and bullies - even from my mother who doesn't know a thing about Youtube - but walls have ears. Until the video was removed.