problem is most instructors try to make you play like they do which may be better than what you do now, but their way may make you worse off.
ive never taken pool instruction and never will.
but i did a bunch in golf. and i found every one of them tried to drastically change my swing, same as they would do to others.
and when in any pressure shot you naturally will revert to your ingrained swing. so that swing is what you need to refine.
they even tried to make me change how i putted. and i putted better than almost any club pro. as that was one of my hustles.
same with your pool stroke and maybe more so.
they certainly will help a novice learn to think correctly and possibly develop a stroke that works.