SUMMARY
If you got a file with a question mark in the path / file name, it won't play.
Remove the question mark and the rescan the local collection an now the file will play.

Note: I'd suspect something with failed globbing or character escaping or lookup/strip of assumed illegal characters (which are of course allowed and usable in some filesystems, in my case xfs and therefore not "illegal") beeing the cause of this. The file is added correctly to the collection and meta tag editing etc works, including from the context menu of the playlist. Just the playback of such a file won't work.

STEPS TO REPRODUCE
1. Create a Folder with a question mark character in the folder name in your local collection folder
2. Put a music file into it
3. Rescan the Local Collection
4. Search the collection for the track add it the active playlist
5. double click the file / Play the file

OBSERVED RESULT
Playback won't start

EXPECTED RESULT
Playback of the selected file should start

SOFTWARE/OS VERSIONS
Windows: 
macOS: 
Linux/KDE Plasma: Kernel 6.6.6-1-vanilla (64-bit) / X11
(available in About System)
KDE Plasma Version: 5.27.10
KDE Frameworks Version: 5.113.0
Qt Version: 5.15.11

ADDITIONAL INFORMATION
Distributor ID: openSUSE
Description:    openSUSE Tumbleweed
Release:        20231219