I recently uninstalled the GNOME desktop. I deleted it completely. I have dependencies in the system that do not allow me to install Mate.
I am by no means an expert, rather the contrary, but I think that MAYBE they conflict because they are different versions? It says fedora-release-workstation-31-2.noarch and the other says fedora-release-matecompix-31-1.noarch, maybe you need the fedora-release-matecompix-31-2.noarch?
If you think there are some packages that didn’t uninstall you could search their directory and do that. Sorry I can’t help more, but you will sure have more lucky in a Linux/Fedora specific forum.
If i’m right (which most of time im not) some packages broken because it’s not same version and my claim because it saying
--skip-broken also it say
--allowerasing (can not see it right) so maybe try it ? (also there is chance to break system but let’s try it)
Welcome to the forum.
I also think Fedora support could be a better place to try in case no one here knows dnf well.
Also here https://www.linuxquestions.org/