Fextralife clarified this as a comment, he saw a monk use a rapier as a monk weapon and so just assumed that it was all weapons you are proficient in.
But rapiers do not have the heavy or two handed property, so it might still be mostly like in 5e.
He also said that you start with two Ki at lv 1, and gain one every level, so you have monk level + 1 Ki points
