Many apps rely on Play Integrity API now which means if Play Store is completely rid off, problems will arise. The latest example was Authy not working on Graphene OS.

Play Store can be disabled and alternatives like Aurora Store can be used however any paid apps can only be linked/used via the Play Store. Except for F Droid, other app stores like what Samsung ships are either full of even lower quality (and quantity) apps. (It has few exclusives but most can be sideloaded).

Only China is a proper example because they have a complete ecosystem outside of Google. From their social networking companies to payment mechanisms, they are usually done by Chinese companies. Huawei has a proper phone outside of Google services, I think, from a major Chinese OEM.

Proper feature parity will be achieved when users need not rely on Play Store as a single stop shop.