AKs joins the calls. A 4-bet pot 500bb deep with one ace-high hand is a commitment nobody needs.
4-betting narrows to the very top; suited hands with nut potential call more. The question on every street becomes: which hands are happy getting 500bb in?
You opened early and got 3-bet by the player right behind you — the most credible 3-bet in poker. Respect it.
Assumes a standard 3-bet; 4-bet to ~2.2–2.5x the 3-bet. Deep, favor calls over 4-bets — a 4-bet pot at 500bb+ commits you with range disadvantage.