I would like to switch back to Xorg. Unfortunately, I do not see the button to switch the session as mentioned here: How do you switch from Wayland back to Xorg in Ubuntu 17.10?
I have the same "issue". Turns out that my system is not compatible for wayland, so xorg is used by default - therefore the wayland based desktop didn't even get installed which leads to not even having the option to switch.
I checked my running processes - I run on xorg.
see this question