I’m using Navidrome and Symfonium on my phone, I have no issues with any umlaut or special characters (å ä ö, japanese, korean, etc) displaying double, did a double-check now as well. Don’t think I had any issues when using tempo either. Things I would check (if not already done): Are the songs / albums tagged correctly Are multiple sources active in the client?

Drop the / in “/data” for the chown command. Now it is looking for a data folder in root, and not the one in “Filmek”.

Don’t know if it will help with your issue thou