bro i had the same problem when playing smash ultimate on my dad's hd tv. the input lag combined with nintendo's online experience basically made online unplayable. the solution to getting rid of input delays is turning on the specific mode, game mode, included in the television. perhaps there is a setting in the mech that allows the user delay-free inputs and he just doesnt realize it.
a 10 frame input delay really does make a world of difference..lol
let's see if our enemy here we find a way around the obstacle!