First of all, I am aware that when a network mount (CIFS or NFS for example) has a broken connection, blocking is an expected behaviour to avoid data and filesystem corruption -- referring to these questions and related.
For programs that are actively accessing these filesystems (that I know about and willingly started), locking up is an expected behaviour. However, my entire workstation becomes virtually unusable when this happens. The problem is, that KDE accesses mounted storage for virtually anything I do -- like opening a file dialog (open/save), even if I don't even touch the affected mounts, or simply opening a program that has those files in the file access history. This causes most programs to become unusable, and I can't even save my work on unrelated drives until the network drive comes back (which may be never).
This behaviour is not acceptable for robust use - especially because it's not expected, it's software trying to be too smart and doing things in the background that weren't initiated by the user.
What could I do to disable file dialogs from querying network shares (presumably done just to populate the special conveinence entries in the sidebar), and treat the filesystem as a normal tree without special entries (the unix way)? Hiding the "network drives" section in the sidebar doesn't help, I tried, apparently it still does it in the background.
I'm not using automount tools, I'm mounting it manually precisely because I want to control when it's mounted (only when needed, precisely to avoid even more blocking syscall incidents). I'm using an up-to-date installation of KDE5 (with Plasma desktop).
disclaimer: I don't know if all file dialogs have these problems, or just KDE-based, which is why I'm framing the question this way.