Greco I would super appreciate any help.
Basically, there are two different ways.
The simpler method is to use a suitable font-family
definition. I would look at typical Japanese websites and see which font-family definition is used there.
This forum uses this one: font-family: system-ui,-apple-system,BlinkMacSystemFont, "Segoe UI",Ubuntu,Cantarell,Oxygen,Roboto,Helvetica,Arial,sans-serif;
The more elaborate but absolutely safe method is to install a webfonts on your server.
But the problem could also be that your machine is not set up optimally as far as Japanese fonts are concerned. (The webfonts method also gets around that problem).
I would exclude a bug in DokuWiki completely, at most an unsupported functionality.
- Michael Sy.