Easy way around
Some years back when Microsoft opened up outlook,com as an email service, I rushed to get my preferred user name @outlook.com.
So, for the Windows 11 installs that I've done, I've always just taken the easy way. I go ahead and complete the OS installation with that outlook.com address. Then, when the system finally opens up to the desktop, the first thing I do is create my preferred local user, administrator account. I sign out of the Microsoft account, sign into my local user, and proceed from there with data and application installation. There is no reason to ever sign back into Windows with the Microsoft account.
Within my local user account, traces of that Microsoft account still linger ghostlike. When I'm in (classic) Outlook creating my email accounts, the outlook.com email account goes right through without re-entering the password. Ditto for installing the Office 2021 suite linked to a Microsoft account (once installed, I sign out of the account within Office to avoid undue cloud entanglement).
Is this approach too easy? Does it entail too much Microsoft involvement for purists?