hldj.org

These 2 commands are somewhat the end of HLDJ. In Team Fortress 2, there is litteraly not a SINGLE server which got sv_allow_voice_from_file set to 1 or sv_use_steam_voice set to 0, so using hdlj won't work on any of these.
I don't know what else I can say, actually.
Is there at least 1 server which allows usage of HLDJ?

Your best bet is to talk to the server admins and other players, or try hosting your own servers. If a community finds HLDJ entertaining then their server admins should know what to do to enable it.