If you click "Domain join instead" on the Azure AD login screen it gives up and asks you to make a local account, which you can then use to join the domain once you get to the desktop.
Domain joining from setup is impossible (it requires a reboot, and then group policy could push something that breaks the rest of the out-of-box experience), so it's safe to assume that will always be there (unless they do a major change to how AD joining works, but they probably won't since they consider it "legacy").
Domain joining from setup is impossible (it requires a reboot, and then group policy could push something that breaks the rest of the out-of-box experience), so it's safe to assume that will always be there (unless they do a major change to how AD joining works, but they probably won't since they consider it "legacy").