(Rav Hutner did not attend opera shows after he became Rav Hutner.)
Regardless, you are really asking two questions, and they don’t really impact each other. One question is if today’s “Jewish music” is really “Jewish”? The other question is if classical music is permitted.
Halachic inquiries must be directed to legitimate halachic deciders, like a Rav/Rebbi with a real mesorah…
But it would be foolish to underestimate the awesome power and soul language of music.