I know it is not going to resonate much with people in English speaking countries, but this has been a major issue for people who use alphabets with special characters (my native Czech included).

For years #PDF viewers on #Linux such as #Evince couldn't save characters outside the basic charsets in PDF forms. It turned out to be a complex problem and multi-year effort, but it's finally done and you can use unicode in PDF forms. First available in #Fedora 37 where we've already backported it.