500bb deep in position, almost nothing 4-bets — the calling range simply outclasses the alternative.
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?
The big blind 3-bets your button open instead of taking the discount — a move that announces a real hand or a real plan.
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.