Warhammer Age of Sigmar moving within 3" of enemy models
I think this is pretty clear, if you trim out some of the extra stuff in those quotes:


  you may not move within 3" of any enemy models


and


  has models within 3" of an enemy unit


It seems clear to me that you cannot avoid the charge phase - you can't move within 3", and you can't fight without being within 3".  At the very least, the intent of the rules are clear, and trying to avoid the intent would likely be looked down upon by your opponent.