Reaching the front page of HN / Reddit / etc is the only way to get support from Microsoft / Google / etc.
At some point during their growth, companies just flat out cut all ties between customers and people who actually work there. The only way for a customer to reach the people writing the code (and able to fix the error 500) is through external channels. Same for billing issues and similar problems too, there's people working in the billing department but customer service is utterly incapable of actually reaching them.
True. It's a sad state of affairs. I doubt many get lucky enough to get this far. I am hoping at least that this is one post nudging the status quo in a better direction even if only a little bit.
Microsoft VP Identity Division, Alex Simons, apologised on twitter and said they will release a fix overnight. I was actually able to log into my account today. But before you get too excited, what they've done is they've completely disabled the sign-in preferences menu and still have the bug - I cannot enable password-less login as it tries to send a notification to my phone, but that is no longer listed on my account. But the system clearly knows about it and wants to send a notification. Unfortunately, it cannot because it also requires it to be a sign-in option. It's a crazy loop of madness.
It would be good this early in the development cycle to devote to Material Design. This will simplify the work later on. Also, making use of Android's accounts/credentials system is probably a good idea for streamlined and simplified login.