If I understand things correctly, the desktop environment is responsible for such functionality. Please let me know if I'm mistaken. :-)

In Windows and Ubuntu (I think) I've become accustomed to using keyboard shortcuts to navigate all open windows, all windows for an app, and workspaces quite well, in addition to simply alt tab'ing and meta tab'ing very effectively.

However, once I started screwing around with Ubuntu's desktop environment, because I kept having a few nagging problems with it, I decided to try out different ones. I've tried Budgie, Plasma, and at least one other one I'm forgetting.

I might be wrong but it doesn't look like KDE's Plasma supports those features. Am I crazy? I was very surprised.