There's a variety of apps that give you manual control. Apple has provided RAW access to sensor data for a few years now and I think some Android manufacturers beat them to it. You're still dealing with a tiny sensor but you can practice and get your mind around the concepts.

Manual mode is available on many Android phones: https://www.androidauthority.com/how-to-take-photo-manual-mo...

I use Moment for iOS, and for awhile, I put its icon where I normally put the stock Camera app (in the rightmost position of the dock). But to be honest, I found myself rarely using it. I'm not sure if Moment's interface is clunkier compared to its rivals, but it's just much harder to adjust and access settings from a touch screen compared to a full-bodied camera's physical controls. And making manual adjustment often doesn't feel right or necessary for 99% of the impromptu photos I take with my smartphone.

https://apps.apple.com/us/app/moment-pro-camera/id927098908

Halide on iOS is one of the best ways to shot in manual mode on your iPhone. You get full control, a histogram, and even manual focusing options. It's a pretty amazing app and totally worth the one time purchase price.

Some third-party camera apps allow you more control (e.g. Samsung camera).

On iOS get ProCamera