If you can't set up without an account, this should work, no? 1. Create an admin user "setup" with a throwaway Microsoft account on first boot. 2. From there, create a local user "admin". 3. Reboot into "admin" with internet off, delete "setup", and run a bunch of deshittification scripts to get rid of AppX(Provisioned)Packages.
If you're going to go through all of this there are easier ways to just work around the install and crap limitations. They are also still annoying, but at least easier.