That privileged plug in /e/os makes push notifications work, and you can enable just those and leave Android Auto, G Play Store and whatnot disabled. Not much privacy risk - I think?

On the other hand, while GOS is running Google services sandboxed, they are still running and have access to internet. If you try enabling them only when you need push notifications, they will break - notifications stop coming.

Neither system is optimal - can we please get microG sandboxed on GOS, pretty please?