As I said, Iowa is not a strong defensive team, especially compared with South Carolina and UConn, but better than in past years. As for your description of what you feel would be a Lieberman Award winner's qualities as a player, here's what the award is actually looking for:
"The floor leadership, play-making and ball-handling skills that personified Nancy Lieberman during her career." And, I'll opine, scoring is very much an aspect of play-making, correct?
There is no mention of defensive skills, and in particular 'taking on a team's best ballhandling guard.' That said, Caitlin Clark is a better defensive player than you credit her, and certainly is the epitome of one who has the expressed skills sought in the Lieberman award (as has, and hopefully will again, Paige Bueckers).
JMO.