I'm honestly torn. I think Amir, KO, and JJ all have really good claims for that spot, and I really actually like the differing fits that each provides.
I think one of Amir or KO probably gets the spot, but I honestly think JJ at the 4 gives them the best two-way starting five. Between his floor spacing/deadly corner 3 and his size/defensive versatility, I think he provides the best of both worlds, especially against a team like Cleveland.