I'd recommend that you try and ask this in a more specialized forum (e.g. BGG [1]). Also, if solo playable board games is a must - this drastically reduces the amount of games.

Maybe also consider card games (like Solitaire)?

[1] https://boardgamegeek.com/

I also considered recommending Solitaire.

I personally enjoy playing Free Cell with a deck of actual cards (although a video game version is just as fun).