On my phone, I have two games:

• PySolFC - FOSS collection of a bunch of solitaire-like games, with varying levels of attention required
• Lichess - FOSS chess game, with puzzles, bots, and MP

The first is available on F-Droid, not sure about other stores, and the second is probably available everywhere (I got it on Google Play).

I, too, got tired of sifting through ad-riddled BS and just didn't play games on my phone for years.