I have not used a TA (online or otherwise) for years. If one books a flight with Trip/CTrip, would the airline status work? Would you get miles?

Sounds like at least for Marriott, it is better to book direct.

I see these Chinese Youtubers travelling in Mainland China getting really cheap hotel rates at local hotels that seem decent. I guess those might be those who are NOT officially "equipped" to handle foreigners?