New
#11
Sorry for the late reply.
I'm not aware of any safe way to change it other than to create a new account with the name you wanted instead.
It's normal for it to use the same name as your "C:\Users\(user-name)" folder.
The separate one in the navigation pane as a separate group uses your full account name instead. This is only when you have "Show all folders" set for the navigation pane though.
I've found that creating a local account with the name you want will have the "C:\Users\(user-name)" folder created with that name. Afterwards, switch the account to a Microsoft account.
@Brink: Thanks! This is the first time (in 22 years of using Windows) that I've been able to show all my Windows Desktop Files (not just the Public or Private ones) in Windows Explorer! Not that I've really searched for a way before or had much need to (since I like to use the keyboard as much as possible and make sure all my frequently-used Shortcuts are accessible via as few keystrokes as possible). However, for those who don't (which are most users), there really is no substitute for this. Users usually have their Windows Desktop covered up by Windows of open apps, and even though you can access the Windows Desktop quickly via the Windows+D key, AFAIK, there's no reverse of that, since if you do anything (like open another app), pressing that key again won't restore your open apps' Window positions. You'd have to manually select each open app again (via Windows Taskbar or Alt+Tab).