Outlook 2016 doesn't accept password or app password

I work on software as well and while I understand the challenges of maintaining legacy code but things that are protocol-based are usually modularly enough to backport. I think this is how MS try to squeeze revenue whichever way it can, i.e., sell new Outlook 2021, get you to use ad-inserted version, sell your data... I do think this time things are done very purposefully - the convenience of it aligning with the "new Outlook" is hard to ignore.

I have moved my data off Microsoft platforms, bit by bit... Giving Google access to some of my data give me much higher return in terms of value! For example for Calendar, Google Calendar lists a picture of the place of the event/meeting.. and Maps alert me to leave while factor in traffic and such. Microsoft's - NOTHING! Microsoft's AI on email and calendar is also terrible. If I book a flight then cancel or change it, Microsoft's AI is too stupid to understand and insert all the wrong/outdated flight information to the calendar but Google's is smart enough to figure all of them out.

No warning but this is how MS operates these days. Every product, whether the OS, Office, Edge, Developer Tools,... they drop changes without much of a notice. No instructions, no whitepaper in most cases... If we are lucky, some product manager makes a blog post. Heck, it's an email account - why not use it and email us critical updates.

It's a free account, and so I don't understand why it doesn't authenticate as OAuth, yet all the registry keys are present.

No warning. No heads up. No notification. No communication. Notta. Nothing.

I may have missed the fact but does anyone remember MS emailing us in advance of this protocol change?