CSV is hardly an easy format to parse, or really produce. There is no CSV standard, and I bet lyrics contain all kinds of weird characters that makes choosing a separator hard.

Newline JSON is a fine interchange format for this, and the only advantage I can see for CSV is you can load it into a database in one command. Which begs the question as to why use a database at all for a simple one-off diff, when there are much more lightweight alternatives (a shell command).

So now you are converting your JSON to CSV to load it into a database to run a bunch of database diffs over it to then compare them in some way. Wouldn't that lead to the question "how did we get this huge problem and is there already a solution"?

Seems like you are the one over complicating things.

And I have to say, choosing CSV and then using a database for this task reeks of inexperience. KISS.