Usually, a Soft Reset (Volume Down and Power, for 15 seconds until buzz), is all you need, to restart the phone, and not lose any data.
It's very rare that you need a Hard Factory Reset,...
Wow. No mention of:
... there's other params too that may help, like:
I think powercfg.exe can help diagnose your issue....
Regarding the Microsoft Authenticator app on Windows 10 Mobile, you said you had to "manually copy" the number. But, you can long-tap the number, and "Copy to Clipboard", then go back to the other...
Are you sure this was fast-ring-only? I'm pretty sure I had a phone enrolled in the slow ring, and it received this update too.
The link in the article, is incorrect.