I logged into it using the same login that I use for my LM Cinnamon session; I’ve heard this is not ideal, and this issue is probably one of the reasons why.
Ah yeah, this will be why. Installing different DEs as the same user is pretty much guaranteed to create conflicts and generally should be avoided. It’s always best to create a new user account for each different DE you want to try out so that it doesn’t screw anything up.
P. S. Gnome includes a Wayland session by default, so you don’t have to install it separately like you do with KDE.