As far as I know, the current working logic of mod is that players who have listened to the etched record will have the cache file of the music data of the record.
If a player has never listened to the record and the URL used for etching unfortunately expires (some websites provide time-limited URLs), then he/she cannot enjoy the music of this record!
So, I think the etched records should store the music data directly on the local/server side during the etching process, just like the records in vanilla.
Another point is, why am I not allowed to use local music files or music files uploaded to the game server to etch records?