Hi,
I can totally relate to the frustration caused by the issue. Surely you need not use a PIN after you use your fingerprint - what happens is it falls back to PIN if the fingerprint is wrong.
Typically, resetting the fingerprint data helps in this scenario.
Press Windows key + R, to open the Run dialog box.
Type services.msc and click on OK.
Look for Windows Biometric Service, right-click it and click on Stop.
Now, go to C:\Windows\System32\WinBioDatabase.
Delete all the contents inside the same.
Restart your PC.
Set up PIN again, and then add your fingerprint.
I’m eager to hear back and work together to find a solution.