eOS works great for me on my fairphone 5, I suspect the model 6 is similar. Just be VERY careful about the anti-rollback protection, read the install instructions carefully and follow them exactly. And don't use the easy installer, it can brick your phone.
https://doc.e.foundation/devices/FP6/install
For everyone else, here are the supported devices:
Postmarket OS isn't? Oh whoa, I just checked for myself, I had no idea, thought it was aosp too!
Cool, thanks for the correction.