In Ubuntu 20.04 and older (And Debian 11, 10 and 9) I can convert Puny code domains with idn to UTF-8 / IDN format idn -t --quiet -a "xxx-tést.eu" Works
I know there are libraries like bestiejs/punycode.js or NodeJS PunnyCode to convert punycode, but I can't find any library that detect punycode languages(Geek,