There were some attempts years ago, the author implemented the same stuff as MicroG does now, I wonder if MicroG is forked...

However 3 years ago I was super excited and got the Alternative Google Store (I think it was BlankStore) installed. It crashed randomly and I was not able to download any App. However I thought that the author would work on it and in some time it would be useable.

Still waiting for that day.

That's why I'm a bit pessimistic about this project...

A better way would be to implement a true container/vm system so google only knows what is in this container, no contacts, no calendar, no mails. Heck, maybe it's even possible to link into that container for the host system apps.