Huh, had no idea KuCoin has ANN thread here and what's even better, their account is still active so hopefully OP gets some kind of answer. I've been sing KuCoin since 2017 and never had any issues whatsoever. Then again, I never had that amount of money there like OP, and never would, on any centralized exchange.
To be honest I'm not surprised why they ask you KYC, because you leave huge funds on there and almost any platform will process big funds withdrawal manually.
True, when you are moving that kind of money you can expect exchange asking for KYC. It sucks, but that;s one of the risks of dealing with centralized exchange when they can do whatever they want with your money. That old saying "not your keys not your crypto" is for a reason.
I see some people even told him to ask in KuCoin thread, which he never did...