As soon as I have time it will be CalyxOS on my current Pixel 2. Once I got to update, no idea when, to a Pixel 5 I'm going to try Graphene OS. Oh, and Linux on my private laptop. I don't think you can do anything else to avoid FAANG's eyes. And MS's. Which sucks, I still remember when the only thing tp worry about was malware, not being spied upon by OEMs. Oh, and being spied upon by three letter agencies and their counterparts, but there is not much you can do about that either way.
Again why are they there in the first place? Also how many eyes are on KaiOS anymore? How sure are we of its sandboxing and all other security/privacy aspects?