Grapheneos has well established its role in the android ecosystem. Having developed and upstreamed features that have as a whole, improved the security of android.

Pine64 has targeted a very different market around extensibility and hacker/maker mindset. However while their phones have a lot of potential, security measures are half baked (microphone cutoff switch doesn't actually cut off the microphone), performance mediocre, and demand missing. While I love my pinephone pro, its not a dailiable device. A phone that cannot access common services like your bank account are non viable for 99% of users.