Pixel with Graphene is as good as you're going to get. Which is pretty good in my experience.
Discussion
I have one. My only complaint is two months or so ago they my battery started to last much less. Usually it lasted 1.5 days. Now it doesn't last even one full day.
Using pixel 5a
Why would anyone concerned about privacy use a Google phone?? It's not just the OS that matters, it's the device, too, right? Am I missing something?
It's not a Google phone. Baseband and OS get rewritten with de-googled FOSS software. Graphene on a Pixel is THE way to get privacy on a mobile right now.
If your threat model includes not trusting the HW modems, CPUs, RAM then I'm sorry... you're fucked buddy.