@zeltak_b – A possible solution for you? Requires a bit of investment.
I myself am a big believer in good quality rotary volume controls (rather than keystrokes); I use Mac → USB → DAC → XLR → JBL NanoPatch+ volume controller → headphones. The NanoPatch is right next to my mouse, and therefore immediately at hand. If I didn’t have that, I would be seriously considering this myself: