My understanding is that no... not yet anyway. Phones with GrapheneOS are not "verified" Android so you can proceed to install whatever.

There will b .indirect damage with some devs likely stopping development as their userbase might get smaller still - if they refuse registering with Google.

And I guess there is a future when Google will start tightening the noose on Android itself, which will likely make alternate Android OSs harder to develop (though I know nothing about these things, I sense this is an option down the line).