Thanks @Sylice for this “update”! You mention:
I get no fc-update command on my Ubuntu server, here’s what fc commands I find:
fc-cache (1) - build font information cache files
fc-cat (1) - read font information cache files
fc-list (1) - list available fonts
fc-match (1) - match available fonts
fc-pattern (1) - parse and show pattern
fc-query (1) - query font files
fc-scan (1) - scan font files or directories
fc-validate (1) - validate font files
Did you mean fc-cache?