Josh,
In this Situation, temporarily disconnect from all of your networks.
Then, back up all of your data from the computer to your external storage device, and then, consider doing a clean installation of Windows 11 OS from a fresh USB installation media drive.
You can create a Windows 11 USB Installation media using the Media Creation Tool (MCT)
https://www.microsoft.com/en-us/software-download/windows11
Regarding protecting your account, may I please know exactly what problem you're having?
Has your security verification method been replaced?
Please see 'How to help keep your Microsoft account secure' and secure your account first.