Hi,
This might happen because your Windows profile got corrupted, so try these steps.
First, go to safe mode with networking so you can sign in using your Microsoft account password, then try to reset your PIN or switch to a local account.
To enter safe mode, on the Windows sign in screen, hold the Shift key and click Power, Restart. When your PC restarts and you see Choose an option, go to Troubleshoot, Advanced options, Startup Settings, Restart. After it restarts again, pick option 5 or press F5 for Safe Mode with Networking.
Now try to reset your pin. Go to Settings, Accounts, Sign in options. Choose PIN, Windows Hello, then pick I forgot my PIN and follow the steps.
If that still not working, try switching to a local account using the link you have, then later switch back to your Microsoft account.
If nothing works, try turning on the built in Administrator. Hold Shift again while restarting. When the menu shows up, go to Troubleshoot, Advanced options, Command Prompt. In the command window type, net user Administrator active yes, then press Enter. Type exit and restart your PC. After restart, choose the Administrator profile, it normally has no password.
Let me know how it goes,