Have you tried to see if Rockbox is suitable? [1] I was unable to find if they support TXXX comment frames in MP3, but saw patches that make me lean towards (p

Have you tried to see if Rockbox is suitable? [1] I was unable to find if they support TXXX comment frames in MP3, but saw patches that make me lean towards (partially) 'supported'[2]. 1: https://www.rockbox.org/wiki/DataBase https://www.rockbox.org/wiki/DataBase 2: https://rockbox-sf.cool.haxx.narkive.com/zvKFjdvm/rockbox-patches-1252758-arbitrary-vorbis-comments-and-id3v2-txxx-comm-text-in-wps https://rockbox-sf.cool.haxx.narkive.com/zvKFjdvm/rockbox-pa...