

Last time I had a PC with an optical drive, I used the built-in features of Dolphin, and using a different software for metadata. If you use KDE, it’s hard to find a good reason to do otherwise. It will usually get metadata from CDDB, but on the other hand for metadata It’s really hard to beat Picard or Beets.
Beets will also scrape the lyrics and add them to the metadata, beside acousticbrainz goodness, multiple genres from Last.fm, and more. Picard will do most of this as well.
What you read is true, and also total nonsense.
There is not too much point in discussing privacy and security without a threat model.
So once you put your threat model into focus, you can discuss how to mitigate those threats and pick the right browser for you.