When I have to boot into Win11, I run this right after as a shortcut from my desktop (right-click and Run As Administrator):
net stop usosvc
sc config usosvc start=disabled
net stop wuauserv
sc config wuauserv start=disabled
.. be sure to set your Wifi points as metered to block Update as well.
Note that anytime you go into certain Settings / Control Panel pages, Win11 silently re-enables the above services! Crazy. (Someone should really write a patch for that...)
Sad anyone has to put up with this BS but, we do what we gotta do.