Sometimes open back is the right call, sometimes it’s not

PC38X just purchased, no sound from right side. Is this a common problem??

I recently got this headset, and wow is it good. My only issue is when certain people talk on discord, I can hear a really high pitched ringing. I fiddled with a bunch of settings, computer audio and discord, and nothing seems to solve the issue. It is primarily if not all in my right ear only. Is there something wrong with my headset, or was that ringing always there I can just hear it cause the headset is THAT good? I haven't had any issues with any other application, though I have yet to test if I can hear the ringing on a different version of discord, say on my xbox instead of my pc. Only other issue I've had is occasional static, but I can't tell if it's from the headset or the show/game/etc.

https://www.youtube.com/watch?v=MB15yM4UptQ

Hey all, What would you recommend I get next and why? I have Koss ESP-95x electrostatic massdrop headphones. These are my first and only audiophile set. I love them. I think my only real requirements is $500 or less for the headphones and that they have a little more low end. I don’t need thump but these are really light on lows…but the experience is still awesome. Also any recommendations on an amp? I only have my electrostatic thingy. I am using the Topping D50 DAC. thx!!