This is going to be my next step as well, after switching to Manjaro a couple months ago. Unsurprisingly, after years of using stuff like Google Photos, Play Services, etc , it is not as easy as just a click of a button, but it's definitely worth doing
I'd like to try Graphene but older Pixel phones are end-of-life or not supported at all. So I again put LineageOS MicroG on my Pixel 3a and 4a. Those phones are super cheap and still great to daily drive. So no Graphene-experience for me, I guess.