Guys, I figured it out. I had linked a school email address to my PC ages ago, and apparently the email account just got deactivated, because Windows could no longer connect to it. On my PC I went to Settings -> Accounts -> Access work or school -> Clicked on the account -> Disconnect.
Tried the Your Phone linking process again and breezed through it, working great now. Thanks for your efforts Greg!
I've been having the exact same problem on my Samsung Galaxy S20. More than a month of futzing with it... did everything that Greg did, some several times over... with no luck. Just deactivated my 3 work accounts on my laptop and voila, like magic Your Phone connected.
Since these are my current employers, however, it remains to be seen what else gets messed up because when I try to reconnect one of the work accounts, I get the error message "your organization does not support this version of Windows." Really? I'm running Windows 10 on a high-end Lenovo ThinkPad X1 Carbon Gen 8 and this account was connected 5 minutes ago.