I do often wonder why it's so rare not to find PC-esque graphics options on mobile games. Particularly on Android where there's so many handsets no developer can even test on all of them, never mind spending time tuning each one.
But even on iOS, the developer might have tuned every single device to their satisfaction, but they don't know the user. Some players might prefer ropey graphics if it buys them 60fps smoothness. Other players might be on low battery and are happy to turn it all down because they're away from their charger.
It's all pretty feasible from a dev's perspective - any reasonably complex 3D game probably has adjustable graphics options, it just seems to be unfashionable to expose the options to the user.
Minecraft & Survivalcraft
Dementia: Book Of Death
There are definitely some more games which providing graphic options, mostly indie games as far as I know. Makes sense cuz Indie Devs can't buy every single device out there to test their games on I guess.