I guess you run a bit of everything, but I couldn’t tell you what every distro is doing with their package manager. All I know is I installed it the same way as most other things on linux using the distro repos and let those guys sort out what versions should be used. I just wanted to point out that the original commenter wasn’t necessarily wrong. That I could in fact follow their instructions and it was there for me as indicated by the screenshot with no further action from me.
That isn’t a good idea. You should never install gnome and kde together on the same system. There are often lots of conflicting stuff. Some distros handle it well, but most don’t.