He pointed out the math is unnecessary complicated in this higher arena yet physicists are amazing to figure the law out among this mess.

QFT is just above QM, then Random Matrix Theory then just ordinary integral in calculus.

Just depending how complex you regard sai, if it’s dependent on one – dimension time, that is Quantum physics, if dependent on space time or higher dimensions, that’s QFT, if its a rigid matrix, not depending on any variable/coordinates, then it’s just integral problem in math.