Tennis: Spacing & Hitting Inside to Out

The correct swing is NOT a gate that swivels on hinges ...it is more like a wall that moves forward thru impact ...once the "wall' cannot move fwd any further (due to arm length), then it pivots left in an aggressive arc across the torso

Do not simply step to the side and hit ball with an "out to in" path ...you must move diagonally back and to the side for the ideal "spacing" to effect your swing (yellow lines)...then step back into oncoming ball and swing "in to out" (shown in GIF)...if you swing in to out properly, your elbow should be still visible from the rear view

make sure wrist is in ulnar deviation and extension in the backswing ... and then release the ulnar deviation into neutral thru impact ... however, at impact wrist is still in extension albeit less pronounced