Krunner, wobbly windows and KDE connect are features of KDE Plasma, not Debian. You can install KDE plasma on arch and use all of the things you listed. Arch also has good app support through the AUR. Plus the wiki is called the Linux bible for a reason
I don’t really have time to watch the video rn, so I’m not sure whether my reply really hits the mark, but what about window managers? you know, like sway and stuff.