Directly? What do you mean? Just use their UnionPay bank card? It seems like you can only send to WeiXin users who have linked a UnionPay card to their account anyway, so perhaps that makes sense to skip the intermediary.
"Who can I send CNY to?
For your personal account, you can only send CNY to private individuals who have any of the following
UnionPay bank card,
an Alipay ID
Weixin ID.
They must have opened their bank account with a Chinese national ID card — we can't send CNY to accounts opened with a passport, driver's licence or military document. You cannot send CNY to businesses using your personal account.
I have used Wise several times to transfer money from UK to my wife in China. There are upper limits of around £3,000 depending on exchange rates as I think the limit is set in $US. It works very well and if you do the transfer in working hours it transfers in seconds. Wise do not work weekends in UK so avoid those times. I have a full account with them and transferring money from my HSBC account to Wise is very easy.
Before using Wise for years I used HSBC UK bank account to my bank account in China and never had problems it took a day or so for money to transfer the best being 6 hours. I have also transferred money from China to UK too. BUT it seems to me that if you you are transferring money from UK to an account with a different name in China it doesn't work. I had a failed transfer to. my step son and eventually HSBC got the money back for me less some fees charged by Bank of China. HSBC could not find out why the transfer was rejected by Bank of China. It was then that I switched to using Wise. However, if you can get it to work HSBC to a Bank of China account is cheaper than Wise.