Currently, the circulating amount is 508 million. I would like to ask why the total balance plus the staked balance is only 448 million, where did the other 60 million go?

The number of coins at the exchange address is decreasing, while the number of coins at the staking address is increasing. Going short now is the least wise choice. $USUAL
If you want to hedge after staking your spot coins, you should short at a high, not now.