gmsCore (microG) is an open source way of using Google Services.
You re-implemented Google Services (albeit open source instead of proprietary), from what I understand you’re exactly as vulnerable as everyone else - But you have a giant “I’m trying to hide!” sign painted on your account.
I like Bluetooth quite a lot, but the default SBC codec that comes with A2DP isn’t all that great. Even FLAK gets recompressed in an obscure format at medium bitrate.
HD “standards” like… AptX(?) aren’t really a Bluetooth standard AFAIK but it runs over Bluetooth so if both devices support it, it works great.
Fun fact, them HD standards are so software based that I got support for three different HD standards when I changed OS.