Review my 1 month itinerary!! Suggestions?

Hi all! My partner and I are about to venture into our 1 month trip to China! I was hoping to get suggestions on our route, especially Xian -> Chongqing -> zhangjiajie -> Chengdu portion of the trip. We are really looking forward to zhangjiajie and are mentally preparing for the physical exhaustion (as it is not something we usually do) and wanted to do this earlier than later while we have the most energy.

South Korea - Seoul - Aug 27-30 - 3 nights
Beijing -Aug 30- Sept 3 - 3 nights
Xi'an - Sept 3-5 - 2 nights
Chongqing - Sept 5-8 - 3 nights
Zhangjiajie - Sept 8-11 - 4 nights
Chengdu -Sept 11-14 - 3 nights
Guangzhou - Sept 14-20 - ~8 nights *business trip
Day trip: Hong Kong and Macau?
Shanghai - Sept 20-27 - 5 nights
Day trip: Hangzhou

Back to South Korea for flight home!

I know the train from Chengdu to Guangzhou is quite long (~8-9 hours) and even wondered if we should break it apart by stopping in Liajing?

Thoughts??

Also note that we haven’t booked hotels after xi’an or any trains…