Way back in 2016, I pre-purchased a SIM from China Unicom. I was able to order from Canada, then have the SIM shipped to the Hilton Wangfujing in Beijing. When I checked in to the hotel, the envelope with the SIM was waiting for me. All I had to do was pop it into my iPhone and all was well for the 10d or so I was in China.

Today the URL - https://www.mychinaunicom.com - goes to "UniMobile" but the same service to pre-purchase and ship to hotel in China exists.

7d / 5GB - $28 USD
15d / 10GB - $45 USD
30d / 30GB - $60 USD

By global standards I guess that's sort of expensive, but for the convenience of getting a Chinese SIM that actually works and you don't need to line up in some store where no one speaks English - well sometimes it's worth paying for convenience.

Nowadays I have an Airalo eSim that seems to work pretty well the world over. But China is China so when I go in December, I'll probably use MyChinaUnicom again.