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.
You will never find 100% safe on third parties, they can be a scam anytime, trust no one is a good thing to anticipate any form of hacking so you can be more careful. Exchange sites are prone to hacking and scams. so you have to be smart in securing your account and you have to be smart in dividing your money into each exchange