marvel rivals replays are recorded at a low tickrate and tends to interpolate/smooth mouse inputs, which makes people's aims look steadier/more snappy then it actually seems.
as for wall pre-aiming, most of your clips you're dying in a very common angle or they are pre-aiming you because they just saw you there? also the game just has built in wallhacks for punisher passive? so you can't really get mad at something that's intentionally in the game