I have a Fairphone 5 with eOS, and I’m happy. Their service is painfully slow, but otherwise professional and reliable. You can run into headaches when flashing eOS if you are not super-cautious (dm mefor details if you like), but the instructions are good, and you can also buy various phones direct from Murena with eOS already installed.
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:
https://doc.e.foundation/devices