Just came back from Shanghai. Stayed at Sheraton Hongqiao and used my CSP.

While checking out, I said "please turn off DCC", the staff asked "you wanna settle the charge in CNY?", I said "yes, CNY please". Done.

The slip completing the authorization says 392.93 CNY (a Cash and Point stay, the rate is usually 1100 CNY and up).

So, my experience is, just ask those big chain hotels to turn DCC off before swiping, and if fails at last, settle with a UnionPay card instead (or Discover).