Not defending windows 11 in any way, but on install, when you get to the "login to your microsoft account" screen, if you open command prompt (ctrl + f10 i think) and open the network utility - type ncpa.cpl, then you can find and disable your network adaptor. Close cmd and the network utility and click back. It will ask you to create a local user.

I've done this a couple of times and it hasn't forced me to create a Microsoft account yet (I use a lot of windows vms). If this no longer works on win11, apologies, it used to.