Volume intermittently goes down momentarily and then back to normal level on iPhone

A few months ago, the volume level on my iPhone X would intermittently go down for 20-30 seconds and then back to previous level. This occurs when listening to music, YouTube videos, podcasts, etc. I figured that maybe it was a hardware glitch due the age of the iPhone X. A couple of weeks ago, I received the new iPhone 14 Pro Max. To my chagrin, the problem continues to persist on the new phone despite being updated to the most recent iOS. I have noticed that it is a widespread problem among iPhone users, but nobody seems to have a fix for it, including Apple. I spoke with a technician last week, and she ran a diagnostic test on my phone, but found nothing. She just told me to take it to an Apple Store and let someone look at it. That’s fine, except the nearest store is around 3-4 hours away. Has anyone found a fix for this annoying problem? Thanks in advance.