In MuseScore 4, overwriting the MuseJazzText font currently does not seem to work.
Here you can find a temporay work around... You mileage may vary...
- Download the renamed font from here and install it on your computer.
- Put this file into the "Styles" folder of your MuseScore 4 installation.
- Open a MuseScore 4 file.
- In MuseScore 4, go to "Format" - "Style" - "Chord Symbols".
- Under "Appearance - Style" click on "Custom" and pick the file you have put into the "Styles" folder (named "chords_jazz-LilyJAZZ.xml") and confirm by clicking on "OK".
Should MuseScore not displey the chord names properly when you re-open your file, you may have to select "Standard", then re-apply "Custom" and select the stylesheet again...
Caveat: MuseScore 4 does not seem to read all glyphs from this font - the D.S. symbol e.g. will be read from the built-in Jazz font...
Edit - no caveat anymore: Found a solution to display the correct symbols:
Copy this style sheet into the "Styles" folder (cf. above) and apply it to your score - job done!
