Thank you all for the discussion above.
I am always resistant to the ‘chasing-your-tail’ upgrade cycle, but I finally decided to save my files & upgrade to Debian 12 for the sake of being able to run the latest versions of kdenlive. I made a clean install of MX Linux 23.1. It was quite painful & it will take me some days to get it the way I like, but I am glad I made the move.
THE GOOD NEWS
I am happy to report the issues of the app not starting are fixed: 23.08.2 issues starting up. No older 23 releases in Archives and also this nagging popup about KIO worker that I had is fixed: [kdenlive] Unable to create KIO worker. Can not find a KIO worker for protocol 'tags'
The latest version (23.08.4) appears to start fine. Except I don’t know what’s up with downloading Whisper speech-to-text components: it doesn’t seem to work properly. But that might be for another post.