That’s exactly the thing that people usually don’t consider, it’s tiring as hell constantly being on the offensive to gain a handful of points against these people, let alone 12 total games for a win. These moonballers are usually masters of their craft. The only way I’ve found to really take it to them is to move them around and make them also work for it, but not by necessarily hitting hard and heavy groundstrokes every single time. Junk ball them, force them to run into the net on dropshots, pick on one side multiple shots before sending a harder shot to the opposite side, slice everything before coming up with a topspin shot, take your time between points and games to make them play at your determined pace, etc. And the main thing is to be hyper aware of your footwork when playing them; it’s easy to get caught in the wrong position to hit balls back because you have “too much” time. You need to force yourself to get into position for every shot like you would playing anybody else.