On my system, a font was available & working in other apps like GIMP and LibreOffice, but not Inkscape. Somehow, that font was found in the system font folder, but not properly "installed" by Windows. A properties query on the font showed it to reside in another folder also, so I used the Windows Install Font process to install from the other location and then the font was working in Inkscape.
I don't think the font was installed by Windows using a shortcut. However, I have found that fonts that are installed using a shortcut are NOT found by Inkscape, but are found and work in Libreoffice. (GIMP seems to ignore fonts installed by shortcuts, with at least one exception: "MT Extra".)
YMMV