Out of curiosity, are you referring to rooted Android, or some variant that provides the user some protection from apps "knowing"? GrapheneOS seems to provide some of this (Storage Scopes, network permission, etc.) but not all.
Custom mod of LineageOS, not rooted stock Android, although you might be able to accomplish it with rooted stock and some frameworks like Xposed, they can be detected by some apps, and some apps actually do detect those frameworks and ban users. WeChat is particularly notorious for this kind of detection. If you get banned you not only are disconnected from communicating with your family and friends, you can't even book train and flight tickets, you can't buy food at many places that only take mobile payments and don't take cash, just for a stupid framework. So it has to be done on the OS level.
I was thinking about getting an xperia, I asked about rooting/custom rom and apparetly unlocking the bootloader will delete keys that the camera needs to run. Seeing as it's designed as a cameraphone first and foremost, that's a bit of a major feature to lose.
Why, as a user, is that story (even without losing the camera) would any of that sound better than just having the app store require that apps follow some approval guidelines about what they are allowed to do with privileges and what they are allowed to do when denied privileges?
Unfortunately, you can't really have sideloading and an app review process. If sideloading is trivial/normalized for users then it'll be trivial/normalized for bad actors wanting to exploit those users.
