I like your “Mantra” term. I’ve used mantras for over 20 years to help each student have a 2 or 3 word – rhythm, or tempo with words*, for their specific needs. Example for someone who slides off the ball to the back foot, I might use the word “hold”, that will represent them bracing the back leg to the instep of the back foot during the backswing to keep them from sliding. So instead of picturing the entire sentence, they have a “word” for the “change” we’re wanting.
* Each “word” represents a single “change”… like “Shoulders” “Rotate” in rhythm, could represent the entire backswing (Shoulders turning around the spine) and the downswing (Unwinding or Rotating the body completely to the finish). So in this example, the complete golf swing has been reduced to 2 words. This is advanced, but I use these mantras for beginners too, to learn setup and other elements. They make practice and routine on the course, simple and repeatable.