I considered getting another pixel with grapheneOS or calyxOS a couple years ago. It's definitely an option, and you can get used-but-still-supported pixels for like $100.

I bought a fp4 from murena because it is supported by postmarketOS, and the postmarketOS support has kept improving. I think the end goal is to run some sort of convergent linux that is as similar to desktop linux in environment as possible. That removes the requirement to completely re-write all the userspace tools for android.

grapheneOS is a dead end as long as it is android based and google and OEMs that are indifferent to open source plight lead android development. A very well written dead-end but a developmental dead end nonetheless.

GrapheneOS developers won't support other platforms because they don't have extensive enough trusted computing "security" features. Trusted computing the nail which seals its own coffin and locks anyone out of running their own OS.