Alternative to GrapheneOS

Im considering buying a new phone and i don't really consider a Pixel. I really like Fairphones approach, with the self repairable stuff. Even though they don‘t have a headphone jack. But well… I can’t change it. I’ll definitely go with the adapter over wireless headphones.

But to my question: What private OSes are there? Fairphone sells FP4s with eOS, how is that? And does it work on the FP5? GrapheneOS only works on Google Pixels right?