Randomizing the kernel location is of marginal utility at best. There are so many info leaks that KASLR ends up being only a small speed bump on the way to exploitation.

Here's a cool project that inventories all your KASLR info leaks: https://github.com/bcoles/kasld

Is Graphene vulnerable to these exploits?

It's easy to be secure if you just remove features. There's obvious tension here.

google has lost its focus with pixel phones

KASLR isn't an effective mitigation against anything, and to me this is part of GrapheneOS's catalog of superficial but meaningless claims.