Al lI can tell you is that I have never had a problem controlling the Premiere Pro playback volume with the buttons and/or knobs on my keyboard. So, no, Premiere Pro does not bypass it.
However, check your preferences and see if all of the audio settings make sense. You might want to grab a screen print and post it here so we can see all of your audio settings.
Just odd how all the system audio including notifications music or whatever stop when premiere is the selected window. Ive reinstalled the audio drivers for my card and have tried a couple things in the audio preferences. No luck as of yet, I suppose I could try a re install of premiere but I somewhat doubt that will fix it since the program itself works fine and its this outside conflict that is the problem.
I feel like an idiot lol. Of the 3 options I had in the audio panel for default device I tried the 2 cards and never tried the adobe one.... 3 days Ive been messing around haha. Thanks trying to help
Sometimes you just need to get the problem out into the open and when showing it to someone, you solve it yourself. Happens all the time. Nothing to be ashamed of at all.