Golf is a game of inches no doubt, and when we are talking about making swing changes it's often a difference of millimeters or degrees. One of the reasons making those changes is so difficult is that we as humans are terrible at controlling such subtle movements. We often feel like we are making the small, subtle changes required, yet when the data comes in there is no change at all. We keep trying to make the subtle changes that get us to the desired change, what players really should be doing is the exact opposite.
Rather than inching your way to progress the fastest way to make a change is to exaggerate it. If you are trying to stop yourself from bringing the club back on the inside, use the first few swings to make an exaggerated change and feel like you are taking the club way too far outside on the takeaway. The benefits of this are twofold, first, if you exaggerate the change then the changes in result should be obvious. If you are seeing no effect from the exaggeration then the change is likely not going to work and you have saved yourself a tremendous amount of time. If the change is showing signs of working, then the exaggerated feel can easily be dialed back to the perfect movement. It is also much easier to feel the change when exaggerating, often when a subtle change is needed it is very difficult for the player to feel if the change is happening in their swing.
Golf is not a game that lends itself to exact movements, instead of thinking of your swing as a movement that you try to replicate swing after swing, think of it as a movement with bandwidths. Consistency comes from narrowing that bandwidth of possible results. Consistency is when even the far edges of your movement bandwidth still produce quality shots. When trying to make a swing change we are looking to find brand-new ranges outside that bandwidth and therefore need to feel exaggerated changes to push the limits of that bandwidth. Once we expand our movement bandwidth to a place that includes the desired movement then the work begins on narrowing the movement bandwidths to create consistency.