Google is becoming more and more a pain the as releasing AOSP. And they're migrating towards more and more proprietary. I think the worry here is having the work power to keep it updated and maintained.
I'm guessing the idea is that with this effort, it makes more sense to migrate to Linux phones instead.
My relatives have a throwaway iPhone 13 with a cracked screen I can use for testing! I'm not sure who to contact or where to start if I wanted to offer it for testing.