Hi ,
The problem is that your username may have been corrupted. You can do the following: change your current account to a local account and migrate all settings to a new Windows account, then delete the old one.
Click the Start button and select the Settings gear icon.
In Settings, select Accounts.
In the left menu, select "Account Info."
Find and click the "Switch to local account sign-in" option.
Enter your current Microsoft account password to authenticate.
Enter the username and password for your new local account.
Set a password reminder question (if necessary).
Click "Next" and select "Sign out and finish."
After converting to a local account, go to the Start menu > Settings > User > Email and Accounts > remove your Microsoft account if you have one.
Afterward, open the command prompt (admin) and run the commands: sfc /scannow and dism /online /cleanup-image /restorehealth. Wait for the process to finish and restart the computer.
Then perform a clean boot and, if you want, uninstall applications that you don't use.
Open the Microsoft Store > Downloads > Get updates. See if it loads. If it does, try logging in to your Microsoft account.
If it fails, you'll create a new local Windows account without your Microsoft account. Go to Windows Explorer > C > Users > your old user > select all folders, copy them > return to the Users folder, and go to the new user folder you created and paste it there.
Then restart your PC and log in to the new account and log in to the Microsoft Store.
Give feedback if the information was useful or not.
Thanks