Hi GMrisingJCLmember1 :)
"Chess understanding" could refer to a specific phase of the game, e.g. openings, middlegames, endgames. It could also refer to elements of a chess game, e.g. Force, Time, Space, Structure. It may also refer to tactical alertness, strategic insight, or pattern recognition. "Chess understanding" is such a broad term it could encompass all of these and more.
I think you have to ask yourself what it is you'd like to improve most and then select study materials relevant to that subject.
Studying games by great masters can be an excellent way to improve your understanding in multiple areas. Studying and playing the Ruy Lopez can help you to learn how to handle a very large variety of positions, hence improving your overall understanding of the game.
How do you improve your chess understanding, what is chess understanding?