Yes I did. So I resolved it in a very strange manner... if someone could explain to me why/how this resolved my issue I'd be super grateful haha.
I went to sound control panel, 3 panels of note:
-Speakers (7-Nahimic mirroring device)
-BenQ GL2760 (NVIDIA High Definition Audio)
-Speakers (Realtek(R) Audio)
Speakers (Realtek(R) Audio) was already set to my default device although the sound bar beside it would not move.
1. I went to my Speakers (Realtek(R) Audio) >properties>advanced>unchecked "Enable audio enhancement"
-This allowed "Test" to actually play sounds from my headphone but I was still receiving no audio from youtube for example
2. I disabled BenQ GL2760 which, even though was not selected as default, was showing a moving sound bar in sound control panel
-This resolved nothing really (at face value at least)
3. I enabled then disabled Speakers (7-Nahimic mirroring device) which suddenly made my headphones work again for music/sound etc.
Super strange sidenote: my Path of Exile (PoE) game was crashing upon launch with steam also starting today when it was working fine last night. Solving the audio issue apparently solved whatever issue PoE was having too.
My new question: wtf is -Speakers (7-Nahimic mirroring device) and why did enabling and disabling it solve my issue when it was disabled to start with?