Hello, I have a similar problem with my phone here: Fairphone 2 help needed: no os, no twrp, no usb debugging anymore - just fastboot mode
After frustrating hours of or work I was at least able to boot into twrp without flashing using the given description here: https://forum.fairphone.com/tags/twrpwoflashing
But I have no idea how to continue from this point now as I have no OS left on the phone. How can I bring an image on the phone again that just bootet into twrp wihout flashing. The only thing I have now is the twrp access with nothing else left on the phone? Can you help me? I would really appreciate any help I can get at this point!