Spreading to different exchanges is a must if you are a trader or if you are staking something to make profit, but still it's risky; we don't have full control of them. That's why you don't put much into exchanges if your purpose is to hold.
Since mine are spread out to Binance and OKX and some of them on Bitget, I'm not worried much if one exchange is shut down since I use them to take advantage of earning from doing some tasks and free airdrops and earn from staking. As I do want to grow them each while trading mainly on OKX.
About the issue above about OKX I don't have an issue using it except the last time that I deposited, it wasn't credited to my account due to the minimum deposit, below minimum but they solved the issue after a few months when the minimum deposit was dropped.
you are right bro!! spreading across exchanges is smart move and it should be a must!! but like you said, it still carries risks since none of us actually own or control those platforms to begin with. that is why it is always better to only keep what you need for trading or staking on exchanges and move the rest into selfcustody wallets to avoid stories that touches the heart. at least that way you reduce the damage if anything goes wrong in the future. i also like using multiple exchanges because each one has its own advantage in a way!!! some give better liquidity, others have good promos or airdrops opportunities. but i don't treat them as tools for storage at the end of the day.