Itinerary advice + thoughts on langzhong

I’m travelling to China in a couple weeks time and wanted to get some thoughts on my itinerary, particularly if I should cut out Langzhong? For context, I’ve added it because it’s en route from Xian to Chengdu and I’d like to spend some time in an ancient town. I think the other possible challenge (other than an overfilled itinerary) is that I don’t speak Mandarin, and it’s a bit off the beaten track. I’d be super keen to hear from anyone who’s been there!

If I cut it, I would probably extend Xian by a night, though I get the impression that other than the major highlights to see there (terracotta warriors, etc) there’s a bit less to do than in Beijing and Chengdu?

I’ll be travelling by HSR.

5 nights Beijing
2 nights Xian
1 night langzhong
4 nights Chengdu