There is a way to bypass registering which you could do on your Android phone, but it’s quite geeky:
https://jacobalbano.com/2021/06/24/s...ut-logging-in/
There are other examples to be found on mobileread as well.
Since Kobo requires you to register online, you can usually register with a fake email address, then shut off Wi-Fi afterwards. So editing the SQL database and giving it bogus information is just an extension of that.
It looks like you just experienced a soft reset which leaves content on the Kobo intact. It could’ve been worse, but who wants to experience that while camping?