I have two games available on mobile. Neither of them require interaction with players, or gathering cards, or lootboxes, or any of that stuff. Just you, the strategy, and the game.

Mindustry: It's an economy game, controlled via strategically placed conveyor belts, mixed with a tower defense. You have to constantly plan around limited space, directions of routers, how to efficiently split resources between refilling your base's supplies and the ammunition of your towers....it's a lot to manage. I've put in many hours playing the newest beta version (has units), and I've only been able to hit about the 60% mark in terms of the technology before getting overwhelmed. The standard release is a bit more stable, but it is a bit simpler (no units, less technology), but still an A+ game.

Rebel Inc.: You are tasked with removing insurgents after a recent war in an area. Your job is to stabilize the region, implement policies to increase security and support, while also organizing your troops to isolate and dispatch any remaining insurgents. It's a hard game, with it being tough to decide between focusing on economy or warfare. Despite having few units (late game, I think I had about 7), and not a whole lot going on in real time, I still manage to lose about 70% of my playthroughs.