this also implies that APEX system modules are going to be a wider problem. If, as it appears, content within APEX modules is unmodifiable to users even with root access to the device, then every future system component that’s moved into the remit of APEX is another part of Android that becomes completely removed from user control.
More investigation is required and it’s hard to know the full implications of that now, but for the many forks of Android like GrapheneOS & LineageOS, and for advanced device configuration tools like Magisk and its many modules, it probably spells trouble.
Maybe this kind of thing can make more people see the benefit of having an operating system that is not based on Android?