But the few times I’ve heard heavy metal, I couldn’t help but notice it was so compressed that whatever fidelity good audio gear brings to the party might not be as noticeable on typical recordings in this genre.
Of course, that wouldn’t hold true for well recorded heavy metal.
Compression can be especially true of some metal, but it is by no means a defining characteristic - so you are correct that there is well recorded/produced metal. Check out the link provided above and simply type in the artist for a measure of compression. Red very compressed (bad?). Green/yellow not compressed (good?). That was an edit - I was initially imposing a judgement, now bracketed.
Many quite well known and contemporary artists who are miles away from metal also issue very compressed recordings. Not that I know many these days, being over the age of consent. Difficult to listen to without quickly becoming fatigued, I wish it were otherwise.