Have you tried installing Windows 11 without signing in to a Microsoft account? It's very difficult to do and the instructions online keep having to change as Microsoft makes it more and more difficult. What I'm finding now [0] involves using a hotkey to open command prompt at a certain part of the installation process and running a command to disable the internet before you proceed.
[0] https://www.tomshardware.com/how-to/install-windows-11-witho...