There is a case to be made that someone in the teens could be.I find it pretty hard to actually peg who is the 2nd best player in the class.
Scoot seems to be the safest bet because whoever drafts him will probably give him the keys pretty early on.
Miller will probably be desiginated to more of a supporting star role for most of his career, so it might be tough for him to actually standout as the clear 2nd best.
Amen's shot will probably prevent him from ever being the 2nd best.
Cam
Ausar
Tay
Jarace
Bufkin
Black
None of those dudes being second best would shock me.