Although this has not happen to our exchange where we put our funds for a long time, this should prove that its not safe to be there for months or years, you have to secure your money, or tokens/coins to your hardware wallet, or electrum wallet etc since you have full control unlike CEX.
Earlier there is a news that Coinex have been hack, where the hacker transfer and drain the wallet, with ETH, Polygon, Tron etc, i think this is the first time this exchange has been hack, i say i have coins there but no value, but if you have lots of eth and others thats is a major concern, since we don't know if they can refund the loses.
so to be safe store your bitcoin and other coins to safe wallet, like hardware wallet etc.
this is the link of the news :https://cointelegraph.com/news/coinex-crypto-exchange-suspected-hacked-crypto-moved
Funds safety is summarized in this phrase "not your keys, not your coins". Never trust a centralized exchange with the safekeeping of your funds as many things could go wrong. The exchange could be hacked, it could go bankrupt or your assets could be freezed as a result of one reason or the other. There have been many cases of these ugly occurrences in the past and sadly people are still making the same costly mistakes. CoinEx hack is not going to be the last, there's always going to be another exchange that will fall prey to hackers, the reputable exchanges are not exempted from the list either. Self custody is the best; get a hardware wallet or a good open source wallet and store your funds.