Don’t 3-bet QQ/AK for value against a ~15% opening range of a player who plays optimally against our 3-bets. We are not doing well against our opponents 5-Bet range and so rather than use as a 3-bet bluff and negate their value we flat.
Against such a player we use QQ/AK as flatting hands to enable us to pay a raised pot in position against a range against which we have good equity.