It's clear after several years that the #1 must have is being stacked over the ball at the top, not kind of stacked, but STACKED. The reason is because without that, I don't have a reliable fixed point of reference to work from to fix any other issues. If I stack one time, then kind of stack, then do a slight shift and lift next, then start getting on my trail side at address, I have no reference point from which to fix anything. Too many moving parts. If stacked, and I hit odd shots, then at least I've got a good foundation for which to discover the flaw. For me that's most likely a lack of lower body engagement on the downswing.
Stacking is also my main focus on the course. Stack, stack, and more stack, because in reality if I'm stacked over the ball, a LOT of other problems are automatically fixed.
Here is a timely YT release from my friend and S&T colleague Rob Cheney on the topic of weight vs. pressure.