I really like Data Wing. Cool top-down 2D arcade racing game with a cool story, free with no ads. It's obvious a heap of passion was poured into the game. Still my favourite mobile game.
EDIT: I use Android so I'm not sure it's on the Apple Appstore but I don't see why it wouldn't be
As a Final Fantasy fan, I've been buying games on PC instead of mobile when I have the choice, but I just started Final Fantasy Dimensions the other day, which is exclusive to iOS and Android, and I'm having a good time.
The only mobile game I've spent any amount of time with was You Must Build a Boat. It's a bejeweled clone with dungeon crawling and RPG elements. It's dirt cheap and has no ads or in-app transactions. I wouldn't have it any other way.
Legends of Runtera. Probably the most user friendly free to play card game. You don't buy booster packs, you buy the cards you want directly and can get enough recourses by simply playing often.
I quite like Dicey Dungeons (a rogue-like, deck builder with a game show theme) and Dicey… Elementalists… which is also a rogue like, deckbuilder… I like this type of game clearly haha.
For local multiplayer, if you can get 4 people together, Spaceteam is always a hilarious time!
I tried a lot, but what felt best was emulating Nintendo DS games that could be played entirely with a stylus. Touch friendly so feels native, but also has benefit of not having ads or attempts to up sell you on a bunch of items that has come to plague a lot of mobile games.