The problem with your device is very strange. My Quest Pro is also having issues with the auto-update. Not the same as yours, but I'm still posting it here in case anyone finds this helpful.
So the problematic behavior is that the device keeps rebooting without any user input. Even though it keeps rebooting, at least it still boots the OS successfully every time, so that you have enough time to disable all auto-update switches before it starts the next reboot. Disabling all the auto-update switches is what stopped this glitch for my device.
I think the cause for this issue is that the currently installed software is somehow newer than the newest available version from their server. This is very strange but you can check for yourself by going to the software update page in your device's settings, and see if the version code of your currently installed firmware is newer than the version code of the update it's giving you.
