You can run GSI (generic system image) ROMs as I explained above, but there are still many glitches. And some Android One devices don't have unlockable bootload

You can run GSI (generic system image) ROMs as I explained above, but there are still many glitches. And some Android One devices don't have unlockable bootloaders, so you can't even flash a GSI. See https://github.com/phhusson/treble_experimentations/wiki https://github.com/phhusson/treble_experimentations/wiki for the list of supported devices and bugs.