Graphene sandboxes Google services heavily, and is enabled and used only at user discretion. It doesn’t get higher priority than any other user application on the device. Calyx is alright but I would recommend Graphene much more than Calyx. I don’t like either of these though unless you are a privacy nut. If you just want to get out of Google, LineageOS works plenty well although without many of the creature comforts of a stock ROM.
I wish graphene supported microG. They’ve decided running closed-source Google (user-level app or not) is the best option, and I disagree.
I’m glad there’s options though.
divest has all the graphene hardening and have unprivileged microg, it also runs on a much wider range of devices.