[Fontconfig] Font selection for "okular" application

[A. Wik]

Hi,

"okular" is a PDF (and other formats) reader, and I'm trying to get it
to use the "right" fonts.

Here is a screenshot of the "Properties" dialog, which shows which
fonts are configured in the document and  which font files are in use:
https://drive.google.com/file/d/1w-imGIDQK2F1dd2pP2yel6vbVQEBr0vc/view?usp=drive_link

The problem is that "NImbus Mono" gets used in place of "Courier New",
and "Nimbus Roman" gets used instead of "Times New Roman".

I have tried to edit /etc/fonts/local.conf and
~/.config/fontconfig/fonts.conf in many ways.

"fc-match" does not mimic the problem that happens with "okular".  Quote:<<
$ fc-match TimesNewRoman
FC_DEBUG=
FC_DEBUG=
times.ttf: "Times New Roman" "Regular"
>>

The system is Linux Mint 21.2.  I'll post more information if needed.

Regards,
Albert Wik.