Microsoft has blocked the bypass that allowed you to create a local account during Windows 11 setup by typing in a blocked email address
Door slammed on last remaining easy Windows 11 local account setup workaround
https://www.tomshardware.com/software/windows/door-slammed-on-last-remaining-easy-windows-11-local-account-setup-workaround
a@a.com is redundant but Shift + F10 OOBE/BYPASSNRO comes to the rescue.