Kind greetings from the Greater Seattle metro area of the USA. I listen to way too much recorded music!
Way back in the 20th century, when I was pursuing an undergraduate degree at Western Washington University, I was enrolled in a student in a Physics 200-level 3-credit course called The Physics of High Fidelity. It was a terrific opportunity to learn how to objectively measure and evaluate audio electronics, as well as to learn about subjective "audiophilia".
The Physics of High Fidelity was team-taught by a physics professor who taught the scientific methodology, and a staff technical consultant who taught about audiophile critical listening and subjective evaluation of equipment. Methinks this kind of course isn't terribly commonplace at universities today, and for the record this was the only physics course I undertook during my undergrad years. I have memories of using the oscilloscopes and other testing equipment and learning about electrical and electronic principles, but other than knowledge from that course and from other episodes of life experience I don't purport to any special skills with diagnosing or repairing electrical or electronic stuff.
Although I've dabbled with some higher-end audio gear in the past, I've regarded the audiophile business with a fair amount of skepticism. Yes, my ears can hear and my body can sense some of the very subtle differences in output from different gear, but I also recognize "confirmation bias" as a human factor in many such evaluations. Most of what I actually own for equipment is 20th-century-vintage medium-high level gear, not stuff purporting to be "state of the art".