There is a youtube channel called "Stunted Growth" that does videos on guys who didn't fulfill their potential. They had a video on RJ Luis there the other day.
(1) They said RJ was projected as a 1st round pick until that final tourney game.
(2) He went 3-17 FGA in the game. Pitino benched him for bad play and bad body language.
His draft value cratered. Said character concerns was a big reason for why he didn't get drafted. But that this didn't seem to be an issue until that final game seems to be an over-reaction to me.
(3) He could have entered the transfer portal and was rumoured to get offers of around $3mil per season by big programs. Instead he went for the NBA Draft.