Enjoying new headphone amp

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.

Greetings, Yesterday I was using my headset like normal with my macbook, just listening to music and on a call with people like usual, and the headset was perfectly fine. The stock wire that came with the headset is extremely long and yesterday it annoyed me very much that it kept getting tangled with itself, so I decided to see if the cable is replaceable. I pulled out the cable from the headset and saw the adapter, and looked online for a replacement. Upon plugging it back in, the audio sounded extremely muffled and washed out. Im not sure what I did wrong to make it mess up like that as I've always taken good care of it, ive had it for about 2 years and its always just been chilling on my desk, but anywho I thought the cable just went bad and ordered a replacement. The replacement came, and the issue is still persistant, so I am not sure what the issue is I've tried multiple different headsets and the issue is not with the port, and I also tried it with my windows laptop and...

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!!