Adding to that one, I'm going to post some more
How they move money from China to Hong Kong?
1. Moving Cash RMB. You can bring 15.000 USD (or equivalent) per day from China to HK and put in a Bank Account. If this is RMB you can easily convert in any money exchange shop
2. Buying expensive stuff. There's a lot of shops where you can buy gold bars, expensive watches using your Union Pay and sell it minutes later for cash that you can deposit on bank account.
3. Insurance. Come to HK, and buy with your Union Pay expensive retirement or insurance plans. Some people are happy to give you cash loans using your insurance/retirement plan as a collateral
4. Crypto. Probably HK is one of the few places on earth where you can sell 2m USD in Bitcoin and get it with cash without questions. Don't try to do that with a Bank account, but you can slowly deposit this everyday (limit is 100.000 HKD around 13k USD) or just start a business and tell the bank that all the cash is from customers so they can raise the limit.
5. Gold. I heard there's ways to buy gold in Shanghai and use it as collateral for a USD loan in HK.
6. RMB deposit. Deposit 10m RMB in HSBC Shanghai and get a USD loan somewhere else. This requires the bank approval for an international merchant transaction. If you don't return the USD, they get your RMB, that probably is not a problem.
7. Horse racing / Macau Gambling. Similar to the above post.
These are they ways I heard off, probably there are much more. It's not ilegal in HK to find ways to get the money out, the definition of money laundering here is different from China,they are more interested in the source of income but not in the way you get it out. Anyway be very careful on doing this, and please don't follow this ways. This is for educational purposes only.
There's no CRS between Mainland China and Hong Kong. The HK Gov tried to make a move on this matter and weeks later you got the violent protests here
How do they get such large sums of money into Macau if there are currency restrictions of $5kUSD?