

You might want to load actual KDE to see if this is a real bug of Dolphin, or if it doesn’t work properly because you’re running it via Cinnamon. KDE apps are very integrated to the rest of KDE, and some stuff need to run in order for them to work properly. So you can’t always depend on another DE’s integral part (as is a file manager), without the rest of the DE.
It depends on the software. If it’s audio real time stuff you need to run, a VM doesn’t help.