Hello.
This could be due to several reasons:
Version compatibility: although you are referring to the latest version of Windows 11, make sure that this version fully supports WUfB features and that all relevant updates are installed.
Group Policy Administrative Template files: Make sure that your Group Policy Administrative Templates file (Administrative Templates) is up-to-date and contains definitions regarding Windows Update for Business. Sometimes these templates need to be obtained from the latest Windows 11 ADMX templates and updated to your system.
Have a nice day.
Best Regards,
Hania