From a **skill **perspective, that is, not about physical size or height - in any sport, an average layman (with little experience in the sport) would be utterly outmatched by a professional player of course, but in which sport is the difference the starkest? (and also, the sport in which there is the least disparity?) Asking about specific positions, too.
My WAG would be hockey; not only do you have to be excellent at skating (which 99% of people aren’t,) but you also need great command over your stick and how to send the puck accurately with it.
A runner-up would be basketball; most average people, under real pressure, can’t make a basket from any meaningful distance to save their life, whereas the NBA pros sink three-pointers one after another with ease any time they are left wide open.