In mobile you can use a lot of games, it doesn’t matter if it’s iOS or Android (or PC), if, instead of downloading the games, you use the ones they offer online in web format (Html5, WebGL , Java, Unity,etc) format, for example here https://www.crazygames.com, which you can play right now in the browser for free. There are a lot of sites like this one. You’ll find also even classic games, like TombRider or Quake among much others. If you want to install a game (RPG), you’ll find the game Eternium in your app store or also in Steam. It’s a Diablo style RPG, with very nice graphics, optimized for touch screen, free to play and not pay2win like others (ingame shop, mostly cosmetics apps like clothes for your avatar and things like this)

Just went through my purchases, and here are some of my favorite. Mostly RPG/MMORPG but with a few others in there:

DYSMANTLE, Hyper Light Drifter, Stardew Valley, Dead Cells, Chrono Trigger, Northgard, Getting Over It, Sid Meier’s Civilization VI, Titan Quest HD, League of Legends Wild Rift, Star Traders: Frontiers

Shattered Pixel Dungeon is probably my favorite mobile game at the moment. It’s a pedant-approved traditional roguelike RPG (most comparable to DCSS) built especially for mobile platforms, and surprisingly one of the best that I have played. It’s also libre software licensed under GPLv3+, though I’m not sure how that works with the App Store. It’s available free of charge on Android but I think it’s a paid app on iOS.

BBTan

Crypt of the Necrodancer, Dead Cells, The Enchanted Cave 2, Slay the Spire, Terraria, and Eternium all sound up your alley

Though it’s not an RPG, I also reaaaally recommend Fancy Pants Adventures. Probably my favorite mobile game of all time.