Just watched a clip of W&K up by the glacier. I've been in similar territory. It's at altitude, inhospitable geography, they're in a foreign culture way outnumbered by people speaking a language they don't understand, with food and water they're not used to, they're jet-lagged, they've been on show on-stop, and the time difference won't help in FaceTiming their children. There's no denying this kind of trip would be challenging.
BUT, I don't think K is as adept at this sort of thing as W, H&M. She looks like the Queen: dutiful, but holding back. Diana, William, Harry, Meghan - they look like they enjoy it, unless it's William looking at semi-clad tribal women, and he just doesn't know where to look. Kate excels at the glitzy bits and the cosy comfortable bits: the gowns, looking regal, Chelsea flower show, anything to do with children (even there in the Hindu Khush). But foreign travel that's outside her normal comfort zone, she look like she's doing it because she has to. William was loving it up there, I really think he believes what he was talking about. Kate looked like she couldn't wait to get back to civilization.