Vampire Survivors seems to fit the bill: no story, a bit of tactics, you level up to get new items, and enjoy killing hordes of enemies at once. After every run you can unlock power-ups for the next run.. It's one of my most played games in the last few months. It's one of the classic "just one more run" type of games
Great game unfortunately it's finishable in about 40-50h. And there isn't much to do after that. You can overnight farm gold but it doesn't really get you anything
Lol I honestly was not sure if your comment was sarcastic or not. I guess you're saying that if you're looking to spend 1000s of hours with a game (like what people do with Runescape) Vampire Survivors is not the best. Still, you can easily get 100+ hours out of the base game + another buch of hours with the DLCs.
Also I think how quick you get tired of it depends on how much you're looking to break the game with golden eggs farming. I personally have not done it but, if you do, it becomes pretty boring pretty fast.
I enjoyed my 50h but it isn't a super long grindy game like OP is asking for.
Also there's nothing to do when you farm golden eggs. You can just keep getting bigger numbers but there are no more unlocks etc. Also the lag is the real enemy at that point.
Second this, it's my usual go to when I want something that doesn't take a ton of brain power. It can also be played with only one hand on the Deck (mapping A and B to L4 and L5).
I was so addicted to this game it was crazy. Finally able to pull myself away now . It's also a fun game to just pick up and have a quick session commuting.