This has reminded me of the the Korean axe murder incident. One of the craziest stories of border conflict I know of.
There is this wonderful old guy who comes into the shop who had the misfortune of working with Korean Special forces in the late 60's. He told me about Blue House and the Battle for the Poplar tree and sent me links about them and other Korean insanity. He comes by and bullshits with me and who ever is around a few times a week. If you studied history by just reading about the things this guy was standing next to when they happened you could stay busy and entertained for years. His body was shattered in Nam, came back and did a thousand jobs, ended up being a ship and port engineer for a few decades. He's interested in everything, reads all the time and has more worldly wisdom than most anybody I've ever met. One of the kindest people I've met in a long time as well. One thing I took from his stories is that Korean special forces guys are a particular and terrifying type of monster.
Not exactly cross-border, but the proximate cause of the Crimean War was a bunch of monks fighting over who gets to put put the star on the tree at Christmas. When you want a war, something's gotta suffice.
You're being overly simplistic. China didn't seize "an uninhabited piece of cold desert high in the mountains" they seized a road along the ridge. This isn't useless desert, this is useful desert. Besides which, if Mexico seized Organ Pipe we'd all lose our fucking minds. India hasn't been in a struggle against Pakistan, India has slapped Pakistan down every 3-5 years since Partition. Never once has Pakistan achieved anything other than embarrassment. China, meanwhile, has been encouraged in their building of concentration camps by no less than the most powerful member of NATO. No one so much as chambered a round in this so discussion of nukes is pure hyperbole. But the fact remains, China managed to elbow control of a ridge by shoving.