I practiced Wushu when I was younger and it was mostly about performing series of routines (i.e. forms) rather than full-contact fighting. We did fight other opponents every now and then, but it was mostly to learn how to properly execute the techniques that we used in the forms. It's not really practical for actual combat though. You could've easily replaced my dao with a ribbon and I would've looked like a Russian gymnast. But it was quite fun.
Nope and yes, by mastering your feelings you can learn to relax and let go instead of bottling up and needing to "release"
Also wing chun as several asian martial arts relies on knowing when to relax and when to tense, to conserve energy and let energy flow freely, it can be very relaxing.
You can also shadow it and slow-mo it, which are forms of training and are very relaxing.
You mayhaps are mixing mental and physical relaxation?
Tai chi would also work, but that is not one of the options.