It doesn't matter what martial arts you use in actual combat, the key is whether you can really KO your opponent. Sanda, Muay Thai and Taekwondo are all acceptable. It's all good kung fu Many people look down on Taekwondo, but actually Taekwondo is very useful in actual combat, because the main technique of Taekwondo is leg technique. Legs must be much stronger than hands. If you can skillfully use a few tricks of the leg, then you will certainly not suffer in actual combat. You said it was impossible to think of a few KOs, and it was definitely impossible to use fists. Fists have a small attack range and are easy to be beaten. If your legs are very strong, you don't need any fancy movements. You only need a few side kicks and legs to KO a few people who can't leg. So, if you can walk, you are better than someone who can't use legs but only fists, and you can fight than him.

The same is true of Sanda. Many times, feet are always heavier than fists. The footwork of Sanda is actually the same as that of Taekwondo, almost the same, but the name is different. Taekwondo may be several times more than Sanda, but the way to kick it out is similar. The most powerful technique of Sanda is actually wrestling. Have you seen China Kung Fu VS American Boxing? The Yankee's fist is actually quite fierce, and his fighting ability is also quite strong. China people kicked him in the face with several side legs, but once he was thrown out, he fainted and was beaten. Anyone who has practiced Sanda knows that the throwing method is very destructive, especially the throwing that feels like the whole body will fall apart after picking it up and throwing it out. So, if you can fall in actual combat, you are a little better than others.

Muay Thai is cruel because its knees and elbows are cruel. Knees and elbows are hard bones, and no one can stand hitting the face. In actual combat, if you can combine your fist with your knees and elbows, the person who fights with you will be unlucky and will definitely be killed.

To sum up: when you are outnumbered, use your legs more, and use your knees and elbows when you are close.

There is no best, what suits you is the best.

I hope I can help you and wish you success.