As for the second question, it seems that you are experienced and know that you have to return to the midpoint after playing, but you can't always think about returning to the midpoint. You have to look at your opponent's reaction after catching the ball (of course, the correct footwork is the premise). If he still wants to put the ball in front of the net, there is no need to run back, just wait for the ball to pick his backcourt. If the opponent wants to put the ball in the backcourt, you should take a step back and run to the backcourt as soon as possible. This can only be observed by playing more and exercising more. It is often necessary to judge what kind of ball the opponent wants to play by looking at his reaction, direction and strength, whether to put the ball small or hang it high, and then make corresponding treatment as soon as possible. However, some experts can fake their actions. Obviously, after seeing his racket back, he will definitely play golf. As a result, he lost his strength at the moment of hitting the ball and became the ball in front of the net. Dealing with such people requires your observation and judgment. This is because I also practice Taekwondo, and my experience is very profound. Often in actual combat with others, it is necessary to judge what kind of leg movements he wants when moving his legs, and then respond as soon as possible, whether to retreat or directly fight back. And some people will give you a fake action, so that you will be kicked for misjudgment ... Hehe, that's all. The key is that you can do it by playing more and exercising more. You must judge what your opponent wants to play, so that you can fight back without being hung up by your opponent.
Wish you success!