I am textbook ADHD, and single-player games rarely hold my attention. The ones that do usually punish me for playing them (cough, cough, looking at the 750 hours I've put into Ark.)
Over the last couple of weeks, I've found myself completely enthralled by the world and story of Subnautica.

Open water terrifies me, but aside from a few traumatizing moments- this game is beautifully stylized, and it doesn't hold your hand. There are a few QOL mods I added after I hit 30 hours of game play, but overall the base mechanics are solid. It's not clunky, and it requires you to think and push yourself if you care to move the story along or obtain better gear.
But, even if you just wanted to hang out in the shallows, base build, you could still enjoy yourself.

TLDR; if you like the art style, survival games, and don't mind ♥♥♥♥♥♥♥♥ your pants from time to time- Get. This. Game.