Xin is such a binary champion he basically is a ball of stats, nothing more. He offers so little to a team besides damage, it's pathecit to cry out over this guy since he is simply bad.
Here is some counterplay to him: Walk. Away. After he dashes to you, you use your stuff, and he sits there, doing nothing because of being melee and having no hard cc beside a knockback that favours 4 out of 5 members of your team and a knockup on a three hit active.
Camille has next to zero counterplay besides flashing her hawkshot or whatever gives her the stupid 40% AS steroid buff, and Rek'Sai right now has probably the worst ultimate in the game, countered by simply walking away, which, surprise surprise, works with Xin aswell.