Even decentralized exchanges or P2P have also been breached,
Hacker Exploits Flaw in Decentralized Bitcoin Exchange Bisq to Steal $250K.
So it lead us to think that no one is really safe, no security features are good because hackers are simply one step of the game. As far as best exchanges, regardless if it is DEX or CEX, we just need to be careful and practice sound security measures like not putting all your eggs in one basket, specially in exchanges.