Currently GrapheneOS is only supporting Pixel phones - and not sure about the oldest ones, that get supported

But here is their FAQ with the current list of supported devices:
https://grapheneos.org/faq#supported-devices

I’m running GrapheneOS since about 2 years now and I’m more than happy.
Didn’t had any real issues with it.
Art the start Android Auto didn’t work, but it does now - although I don’t really use it.

I have Google play service stuff installed, but sandboxed.
And my banking apps work just fine.

Friend of mine made the switch a few months ago and haven’t heard of any complaints either.

Can highly recommend it :⁠-⁠)