@Gabagu Well, is not like he was just letting himself get hit. That just shows the gap between Maria and Ha-min. Last chapter it was said that she's already a pro level fighter so she's basically a cheatcode. And is not like she beats her opponents based on physical strength, in fact it was stated that she's pretty average on that departament, but skill.
She's beating up people that's physically stronger because she's far more skilled. Is basically a pro fighting amateurs. And she's not even going all out. We haven't seen her use any grappling or submission moves yet, other than her breaking that dude's arm. Why? Because she doesn't need to.
Also, MMA fights are not supposed to look pretty or flashy. They usually look more like a slugfest. Having said all of that, some of the other fights not involving Maria have showcased a bit more on the martial arts side.