However, we don't directly dev in Kotlin or Swift, we use Unity, which can export directly to an APK, or an XCode project (which has to be compiled a second time which is a nightmare). Sometimes we have to write native plugins to access device specific features (Last time I needed to was to access the FoV of the device's main camera), but it's not common, Unity has great support for most things you want to do out of the box
EDIT: I forgot, there are some situations where we supply an android or ios app to clients through our own app store, but I believe that devices have to be "enrolled", especially for ios. Generally though, Joe Public will want apps through the official stores
Because personal computers are a legacy platform for nerds and programmers, and smartphones are the most widely used consumer computing platform in the world. This desperately needs regulation. Unfortunately the EU is currently regulating the duopoly into law, making their phones necessary for ID verification, so we're probably completely fucked for at least a decade or two before we even have a chance, but that's still not a reason to shrug our shoulders and accept it.