Regarding the prediction that the rebound high point is 3600, why did I start shorting around 3168?

Because predictions are not actual, at each stage, with each upward move, the probability of a decline becomes greater.

For opening positions, from 3168 to 3260 or even to 3420, each time either a pullback is eaten or a break-even stop loss is set.
Without incurring losses, you can keep testing the top.
Each time you open a position, you use 10% of the funds in a tenfold contract; after a loss, it is added to the next trade.

For example, opening a tenfold contract at 3168 with 10% of the funds, setting a break-even stop loss at 3165, and opening a position at 3260 involves using 20% of the funds to add the previous loss to this trade, and so on.
Eventually, you can test the high point without loss.

This is why every time I set a break-even stop loss, I notify that you can choose to close early for profit.
Closing early for profit means giving up the opportunity to continue falling.
Each break-even stop loss does not really just cover transaction fees; it’s like you never opened a position.
Instead, it’s about continuously testing at zero cost, optimizing your position to the best possible level.