MacOS is fine. It's not as locked down as iOS is. You can even install apps without the app store! :)
I use stock Android and not graphene, so I'll have to bend to this too--same argument 😉. But I do love me some Linux.
Installing Graphene on a Pixel is very, very easy. I think you should do it!
I'll give it a shot at next phone upgrade epoch
We have AltStore, SideStore on iOS....
We have zap.store on Android. :)