The good news is that you may still be able to erase the laptop and reinstall Windows without recovering your Microsoft account, provided there are no additional firmware or device-management restrictions. However, I'd like to clarify a few important details before recommending the next step.
When you say the OS drive is locked, are you receiving a BitLocker recovery screen asking for a 48-digit recovery key, or does Windows simply say that you've entered the wrong PIN too many times? When you attempt Troubleshoot > Reset this PC > Remove everything, what exact error message prevents you from continuing? What is the laptop's manufacturer and model?
Since you don't need to preserve your files, a clean Windows installation using bootable installation media is the most practical alternative if the built-in reset remains blocked.
You would need to create a Windows 11 installation USB using another working computer. You can use Microsoft's official tool:
https://www.microsoft.com/software-download/windows11
Booting the laptop from this USB would allow you to reinstall Windows and erase the existing partitions without needing your previous Windows PIN or Microsoft account password.
Please be aware that this permanently removes the existing data, and a normal USB connection between two computers will not accomplish this. The USB must be prepared as bootable installation media.
Before proceeding, please share the exact message displayed when the reset fails. This will help determine whether you're dealing with a BitLocker recovery requirement, a Windows sign-in restriction, or another issue.