Just be careful if you test several android roms, the phone uses anti rollback (ARB), like pixel phones. In certain circumstances it’s possible to brick the phone, and you’ll have to send it to fairphone.
With android roms that allow relocking the fairphone bootloader (Calyx and Divest for instance), really check if the bootloader can be relocked via fastboot command-line, it will brick if it’s not the case.
I spent some time reading before attempting anything on it and it went rather smoothly, I don’t hop a lot between roms though.