Just Gigabit, or the ethernet connection as a whole?
I think it's more likely a router/network problem than the Q10 Pro if connection is intermittent.
If you do want to do a factory reset then the method to do it properly (presuming you are running Android 7 firmware - you likely are) is to install firmware 2.0.3 followed by the firmware you want (2.1.4 is last official version). Firmware here: https://www.futeko.com/newforum/index.php?topic=711.0