If you want to increase easily the security of your coins you can do it by a simple step. Just withdraw your coins from the exchange to a personal safe wallet where you have the private keys. In case if the exchange gets hacked your funds are safu. Never store more in exchanges than you actually need for buying other coins.
A crypto hack can also happen to big exchanges, like it happended to Cryptopia, a big exchange from new zealand where huge amounts of crypto funds were stolen from people that had their coins stored on the exchange when the hack happend. All users that had withdrawn the fund before were safe because they stored their coins in their own wallets.
Even big exchanges are no guarantee that they can't be hacked, so better be safe and store your coins yourself.
Storing your coins safely will prevent your coins from getting hacked and you won't lose your crypto by exchange hacks.

It's not good to store majority of your coins in an exchanges. I know some people that does that, just because an exchange is a big exchange doesn't mean that it can't get hacked, it is possible for it to be attacked by hackers, not only small exchanges are targets. Even Binance was hacked recently, and that is going to teach some people a lesson for storing coins in exchange, and that's for sure. If you don't want to hear stories that touch, then it's best to just store a bit of your coins in an exchange, and this should be the coins you're trading with, then the rest should be stored in your wallet which is very much secured.