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
Lack of knowledge about wallets is the reason why some people keep money in exchange. The first person who introduced me to cryptocurrencies introduced me to a centralized exchange. It took personnel studies for me to know that decentralized wallets exist. Keeping funds in a crypto exchange is more riskier than keeping it in a traditional bank. They will always give you reasons why exchanges are important but nothing is as good as having full control over your finances. CoinEx has claimed that the funds lost from this hack will not affect customers' deposits because the funds they have in their reserves can compensate all the victims.