Well, take a look at LineageOS and the associated microg edition. They work on dozens of devices. I’ve been flashing ROM’s since the first Android phone and I’m still using my Pixel 2XL, degoogled. I still have my Moto X 2013 {with custim, now unusable ROM} because it is like a river rock. It feels great to hold.

Google phones have always been unlockable - primarily for the benefit of developers.

Calyx also offers a degoogled Android, focused on privacy like Graphene.

If one wants a phone and own it, Google is the only sure way right now.