I want to know the answer to this also! Total photography noob contemplating getting a new iphone here, is it possible to use a different camera app to disable a bunch of the computational magic?

Yes, and https://halide.cam/ is an excellent choice if you want more than the native RAW mode offers.

I only shoot RAW, it does require post-processing to get social media looking photos if that's your bag. (Normies want the pop, not the accuracy; nice it has both.)