I am apologetic but did you actually read the multi times linked [Solved] Windows does not see my phone in Fastboot mode?
There are a number of approaches including a fresh start with drivers. The gif approach does at least include the idea that you might be better directed to Google flavoured drivers rather than specific Fairphone. Fairphone 6 additionally is very new. Continual updating wrong drivers does not seem the way to go. The provision of Fairphone Drivers is a little “unusual”, and the specific difficulty hard to see from this distance. I do not think a new Windows install is required.
However in light of your future anticipated success I will be happy to include anything you learn wrt Windows 11.
Good luck.
Edit. Here is a Windows drivers success story Sdkmanager / adb install via Raspberry Pi OS? - #4 by beta-L-user.