Hans, for the many thousandths time, THANK YOU!
mygrande.net.PNG
Here is my problem. As you can see when I go Settings > Email and accounts, I see the display as in the screenshot. The first user account listed is, apparently, the primary or controlling account. I cannot log in with Microsoft with that account because I no longer have the password for the account with that email address. Furthermore, I cannot use the Forgot Password recovery because I cannot receive email at any email address containing that domain name because I no longer have an account with the ISP that owns it; and my current ISP will not process it. IOW, Microsoft wants to send me an email message to change the password for the account with the inoperable address with the domain hot.rr.com.
The second user account has a different email address with a different and valid domain name that I can sign in to. As you can see, if I select the second user account, I have the options to Manage or Remove the account; however I don't want to do anything to this account. When I select the first user account (with the bad domain name), I only get the option to Manage the account which, when followed, never leads to an option to update the email address. I am not given an option to Remove that account.
I had to set up the second account to sign in at Microsoft.com. When I discovered that both accounts were in Windows, I had hoped to use the second user account to delete the first; but that is not allowed.
As I reported in the OP, apps are apparently defaulting to the email address associated with the 'primary' (but useless) user account.
Does this trigger any other thoughts for how to approach resolving this problem?

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