MicroG is possible to run on GrapheneOS but isn't recommended since GOS has a sandboxing solution for running Google Play apps:
https://grapheneos.org/features#sandboxed-google-play
Graphene generally seems to feel that running official signed Google adware is more secure than using open source alternatives that might require signature spoofing or having root on your own device.
Graphene generally seems to feel that running official signed Google adware is more secure than using open source alternatives that might require signature spoofing or having root on your own device.