Based on what is Kun incapable of replicating those showings in life? As I said, he likely repelled Aleema’s attack at her, which just knocked her out. He never expended any worthwhile effort on her.
And your concession’s accepted – statements make it perfectly clear that Kun’s more powerful than he is in JA – feats don’t matter because Kun’s upper limit in life was never shown and absence of evidence is not evidence of absence.