Hi,
Do you have an option to "sign in with your password"? If so, please sign in using your MS account password. If you can log in using a password, reset your PIN in your settings.
If it does not work, try resetting your PIN from the Microsoft account website.
- Go to https://account.microsoft.com/profile/signin and sign in with your Microsoft account.
- Click on the Security tab and then Update your PIN.
- Follow the prompts to reset your PIN.
If you're still unable to reset your PIN, consider setting up a new local account on your computer. Just go to Settings > Accounts > Family & other users, then select "Add someone else to this PC." Follow the on-screen instructions to create the account. Once it's set up, you can sign in using a password rather than a PIN.
If the previous steps don’t resolve the issue, you might need to try a system restore or reset your PC to its original factory state. Keep in mind that this process will delete all personal files and custom settings, so be sure to back up any important data beforehand.
Source: Can't reset my sign in pin.
I hope this will help. If you need more assistance, please let me know.
Stay Safe!