The sysadmin part is their value-add. One reason my current phone being an iPhone after being 100% Android for a decade are the better walls and nicer garden.
These are sold as consumer devices and not general computers. It sounds like you want something different. They’re selling cars and you want a motorcycle.
Android was very open when it was released and for some time after. Installing APKs directly was easy. Most devices had unlocked or unlockable bootloaders. An Android phone treated its user much like a PC did.
More sysadmin-as-a-service type stuff is fine as long as the opt-out is easy. This isn't. I'm upset about the rug pull.