I recently discovered Celeste and love it so far. It's a skilled platformer that doesn't seem as punishing (edit) compared to other platformers that I've played, but still challenging enough to be satisfying. (edit: And the base story difficulty is not as bad as some other platformer games). The story is also really nice (overcoming depression and mental health stuff), not something I usually play but I was really engaged with it, and communicated in a nice simple way (not a ton of cutscenes like story-heavy games). edit: Celeste is similar to Hollow Knight, though I got stuck at a part of Hollow Knight and haven't picked it back up in a while. Celeste is much easier than N++ and Super Meat Boy, IMO.
(I had intended to play it on my 4k TV, but I found that it has a significant delay that makes it hard, and I somehow didn't notice it in other games. It's much easier to play on my PC).
Also RE the OP's mention of simple phone games, I really like "Simon Tatham's Puzzles": iOS, Android on Google Play and F-Droid. It's a collection of simple puzzle games that I enjoy idly playing for a few minutes at a time.