unwat Thanks for the link. I wondered because of my previous experience with Huawei's aggressive power management, since they often killed processes if the app didn't use persistent notifications to stay in the foreground.
I did notice that GmsCompat itself is battery-optimised by default, so I suspected it might simply spawn as needed.
I'm new to both GrapheneOS and all things Android above v10, so still learning what the expected state of things are.