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.