Well that should all be fine. I don't know much about KDE. In fact I am not a fan at all. Just doesn't fit me at all.
As a lot of folks do seem to like it though, I try to keep an example of it on my external drive. Right now it is PCLOS Full Monty.
If I pull up Dolphin the partitions are listed by label.
If I pull up Konqueror and spend half an hour fooling with it the side panel shows the partitions by label.
Have no idea what to do with Krusader that looks like Midnight Commander on steriods configured by a maniac. It does offer to mount a data partition by name though.
If you open a terminal and, as root, run;
what do you get.
Post that here.
Hopefully I will be back on some DE with a real file browser on it by then. No wonder KDE has so many. You need that many to get anything done that a real browser would do on its own. Sorry, I do have it on here, no one twisted my arm, I just don't like KDE and am prejudiced.