According to your description, the most important thing is entering system firstly.
So just enter your Microsoft account’s password, what happened? It is the most direct method.
If you forget the password of Microsoft password, go here to Reset a forgotten Microsoft account password
https://support.microsoft.com/en-us/account-billing/reset-a-forgotten-microsoft-account-password-eff4f067-5042-c1a3-fe72-b04d60556c37
If you can’t get the password of your Microsoft account, can you have other account for login?
If you don’t have other account for login, you need to restore system to a previous time point in WinRE.
Also check this case for some ideas.
Locked out of Windows 10: login no longer shows Administrator, but only an account that I never used
https://superuser.com/questions/951907/locked-out-of-windows-10-login-no-longer-shows-administrator-but-only-an-accou
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