Maybe I am reading too much into the question, but backing up the config requires logging into the Orbi, which cannot happen without knowing the password?
Before doing the Factory Reset, what about the Password Recovery option? i.e. open a web browser and attempt to log into the Orbi three times in a row. That will bring up a screen offeringn to attempt "Password Recovery" which requires knowing (a) the Orbi serial number from the product label and (b) answers to two security questions that were supposed to be created during the initial setup.
If this cannot be done, Factory Reset is the ONLY option.
