liveCD cannot login unless you switch to Wayland

Maybe there is some reason (nvidia?) to do it the way it is, but as I posted in the ‘solution’ to the linked thread - I believe the default session should be wayland and if that were the case this problem would disappear.

Er .. it is the other way around.
The answer is to switch the session to wayland.
(Because the default session is x11 on the ISO.)

See the marked solution to the linked thread for example;

..as well as the title of this very thread.