Being able to change a User Name and the User Folder is very handy.
Microsoft don't make this process easy, but is not difficult when you know how.
If you are not comfortable playing in a command window and the registery, then forget it, this not for you.

Procedure

Windows 10, 11

Step 1

Find and open the Computer Management app using keys “Windows + X”. Go to the Local Users and Groups section from the left pane. Here, you'll see a folder named Users. Right-click on this folder and choose Administrator from the context menu.

Right Click “More Actions >
  Click Properties
     Untick “Account Disabled”
      Click “Apply”
       

Log Out Of Windows
Log back in as Administrator

Change the user profile folder name in the Registry

1.Open A Command Window
  Search "Cmd" and run as Administrator
Type the following command to determine the Security Identifier (SID) of the account to change the profile folder name and press Enter:
  wmic useraccount get name,SID

2.Pop Up the Run Window >  Windows + "R”
    Type Regedit and press “OK”

3.Browse the following path:
  HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\WindowsNT\CurrentVersion\ProfileList
4.Select the key showing the SID for the account to change the folder name.
5.Right-click the ProfileImagePath and select the Modify option.
6.Change the name for the user profile folder without altering the path.
7.Click the OK button.

8.Open File Explorer

9.Browse to C:\Users:

10.Right-click the folder profile and select the Rename option.

11.Confirm the name for the folder exactly as you typed in the Registry key and press Enter.

12.Sign out of the built-in Administrator account.

13.Sign in to the modified account.

14.Find and open the Computer Management app using keys “Windows + X”. Go to the Local Users and Groups section from the left pane. Here, you'll see a folder named Users. Right-click on this folder and choose Administrator from the context menu.

15.Right Click “More Actions”

16.Click Properties

17.Tick “Account Disabled”

18.>Click “Apply”

19.Log Out of Windows.

20.Completed.