I had an "ah ha!" moment just yesterday screwing around in front of the mirror that I thought I would share. It may or may not help you. First I'll tell my life story...
My issue has been a super inside take-away leading to a late wrist hinge, leading to a laid off club position, leading to a stuck behind me deal, leading to a changing of spine angle to keep myself from hitting it 3 feet fat, leading also to an early release, leading to a decrease in distance and inconsistent ball striking. Hooray for cascading errors. Even with this fault, I like you, play pretty good golf due to a solid short game (5 index) but need to be able to hit more greens from 160+ yds to take my game to the next level (you didn't say this... but I can feel your pain and know it to be true!).
I think the ingrained issue is that I've always been taught to "hinge your wrists late to get width," "bring the club back inside," and "keep your left arm connected" which I've done to an extreme amount for each. Attempting to fix this problem has had me either swinging outside or picking the club up more in trying to not come inside. The issue is that I've been so concentrated on the club head that I haven't been in tune with what is actually going on.
So, to the moment of clarity. Working in front of the mirror I noticed not only how far my club head was coming inside but how far my arms were coming inside. Arms inside + club inside = too much inside. It was painful to see how obvious it was. Now we know that we want to swing some inside because we love the beast-mode draw that we hit when we are on time. What I've been working on is making sure my HANDS go straight back BUT STAY LOW
(keep some downward pressure in the whole grip don't let the hands raise) and hinging the wrists (not lifting them) earlier so that the but of the club is pointing somewhere between the ball and my feet but is still able to get somewhat inside as it should .
I haven't had time to hit a lot of balls this way so the jury is out but so far it looks and feels better. I apologize if the description isn't great but this is what I would recommend. Take an iron and set up your stance with a mirror to your right (so you can see your club and arm planes) and rotate into the initial part of your swing getting your left arm parallel to the ground. If you can look back and see your left arm is pointing more directly into the mirror as opposed to back behind you, and the club is hinged setting upward as opposed to behind you, you'll be on the right track. The keys are to rotate (not lift) into your swing, keep the hands low and straight back, and hinge earlier than you think.
Again, I apologize if this was convoluted or not helpful, but this sensation I've found seems to be helping me and I know how it feels to be stuck in this rut!
Jared