Like above comments, once you’ve set up with the intention to hit the ball - everything that comes after that intentional setup should count. If you’re good enough to accurately hit a tiny ball hundreds of yards - then you’re good enough to stop your swing before hitting the ball. As some people say, golf is as much a mental game as it is a game of striking the ball consistently.
I've been told in a couple of workshops that there are two kinds of officials. There are those who have made an incorrect ruling, and those who WILL make an incorrect ruling. As I read the definition of Stroke, if Pieters began the forward motion intending to hit the ball, and couldn't stop himself from hitting the ball, its a stroke. if he decided during the backswing, its not a stroke. A putt is an ingrained motion, back and forward, so I suppose its possible to decide during the backswing, but be unable to physically react quickly enough to halt the forward swing. That seems unlikely to me.
Every time I want to get new clubs I just go for different shafts. Especially different weights. I own a set of Titleist 718 AP2. I have gone from factory white AMTs, to XP95, to Project X LZ 5.0, and now to NIppon 950GH. Every time I change shafts I feel its a totally different club.
In my opinion, it is shaft weight that makes the most difference, not shaft flex.
AFter many years of playing I have concluded the driver is the most forgiving club, if you hit it right. My problem was a slice, no matter what I did. Until I saw this video about keeping the club head behind you.. Slice solved. Hope it helps.