I bought a Pixel for it (I needed a phone upgrade) and installed GrapheneOS immediately after bringing it home. There was a little bit of friction because a few things weren't working out of the box for me, like Android Auto and a few apps that use GPS (I tried to Pokemon Go, for example) but all these issues went away eventually. The only thing I miss is tapping my phone to pay for things, but this isn't a GrapheneOS issue, (bank/card providers in north America and their reliance on Google Wallet/Apple pay are). There are financial institutions from other countries that offer tap to pay using their own app.

I love being able to select what files/contacts each app has access on my phone. I like being able to disable my camera/microphone for all apps with a simple touch.