I too fought the dastardly low duck hook something awful this year - as you say it is a round killer, absolutely demoralizing. I've golfed seriously for 14 years and this just crept in this year - CONSISTENTLY, never ever had to deal with it before. Like you, it only affects my driver, not hybrids/irons. So I fought it all year and spent alot of time trying everything under the sun to fix it. At end of season, after an incredible amount of work, I did fix it. It turned out to be a simple fix - it is a grip issue (for me).
I always set up with my driver with club head lag like the rest of my clubs. My fix was to set up straight to the ball - NO LAG (no shaft lean). What this does is slightly rotate the grip in your hands ... automatically, You won't have to intentionally change anything with your grip. It will feel really weird, but lock in the grip with no shaft lean / clubhead lag & swing normally. Its pure f'n magic - completely fixed my low short duck hook without any other change in setup or swing, ball position, ball height, etc. Back to hitting nice high straight balls, even a tad of fade sometimes, which i'm fine with. Grip still feels really strange & I have to ingrain it in my muscle memory over the winter indoors, but can't argue with the cnosistent results the last 7 or 8 rounds of the season.... absolutely mind blowing what a simple little change can do.