So basically you want and high reputable exchange that never be a victim of hackings or not possible to get hacked so it will be totally safe for everyone to store their funds? That kind of exchange won't be exist, hackers will be always smarter time by time. Also, everyone are supposed to not storing their assets on any exchanges. You can trade and make profit there but store your assets only on your private wallet.
We don't need to have that kind of exchange as we are supposed to trust no one.
Some cases of hacking on exchange sites may only be manipulated, or insider trick. so the risk is not only hacking but a scam too. that's the risk if you use a centralized exchange site dude, they can be hacked or scam and lose you. You right, there are no exchange sites that are totally safe, there is definitely a risk of losing. but my advice is use decentralized exchange to reduce the risk