Hello, this is Emily.
It sounds like you device is linked to some organization group policy. Go to Settings > Accounts > Access Work or School, see if you have a work or school email listed there? If so, click on it, then disconnect. Restart the computer and see if that addresses the Windows Hello issue.
If I can take a guess, you probably use Microsoft 365 via a work or school account? If so, when you set up Microsoft 365 and signed into your organization account, there was a pop up asking if you allow your orgnization to access Windows settings, you probably didn't pay attention there and clicked Yes. This will then allow your organization's security policy to apply to your computer, usually it will require stronger PIN, and once set up, it will not allow you to change locally. If you ever see that pop up again in the future, uncheck the box to allow it, or choose "for this app only".