You see it as a simple move between two network folders but technically it is more complicated than that.
I think your issue comes from a limitation in the kio modules.
Unfortunately I see no simple waving a hand and it works … that is how it is with Linux.
You can try to solve it in three ways - neither is straight forward - that is the way.
The first is to use gvfs which is a framework similar to what Plasma tries to do but more reliable and accessible as it is not hidden deep down in Plasma depths.
The second is to use systemd units to do the lifting - when the units are created and activated - it will work in the background ensuring a seamless experience. This one is linked by @bedna in a previous comment - it actually consist of two parts - the first with the technical details, the why, what, where etc. while the second is some example units
The third option is a package called smb4k - the reason I mention it last is because I have not had much success with it - but alas - you should know it exist.
sudo pacman -Syu smb4k