we almost don't use google services nor apps. only exception is their maps (please don't start origin of android thing here), but having framework on the phone is enough for that app to be used as a backup one in case of FOSS unreliability.
i'm not against closed source, i just use as many open source services services and apps as possible and i rarely need to change that.
that might be accessible with api2 and for instance opencamera software, but there is no one to answer these and other unknowns…
personally i can't see nothing on MIUI that i need or cannot be replaced with FOSS alternative. Having to maintain two phones under different ROMs gives me nothing but frustration. It's bloated with XIAO solutions that are redundant, complicated or dupe what already is implemented in android. i often have problems finding a simple setting…MIUI have most of complete function like compass, mi fit, lock lost phone. I don't know what do you mean bloatware, and lesser problems than custom roms. If the phone is working fine why bother to flash custom roms?
anyhow i don't see why this digression is important as everyone uses their phones accordingly to their needs and since LOS is available on that devices all i want is just feedback of what works and what still causes problems.