Hi Norbert, thank you very much for your reply.
[...] - added configuration to /etc/fonts/local.conf (easily findable on the internet what is necessary)
I really tried, but I could not find a guide how to do so. I found https://wiki.archlinux.org/title/Font_configuration but it seems not to have a section to configure fallback fonts. Could you point me to a guide or maybe post your XML snippet here? It would help me a lot.
This is not specific to KDE, but to fontconfig and how Debian handles fallback fonts.
So maybe this is not related to KDE directly, but I still think its an unfortunate situation, and fixing at would significantly improve the user experience? Would it make sense to file another bug report against the appropriate package, e.g. fontconfig? Best regards Max Görner