Highest mountain in S.Korea is 7000’ while the Himalayan Mountains are at 25,000 to 29,000’. Not even in the same ball park.
What will determine the outcome is whose soldiers are more brave. During the last border skirmish, the Indian military was outgunned but fought to a stalemate because the soldiers stood their ground until killed.
Note that it was the Indian troops fighting with the British who were responsible for defeating the Japanese troops in Burma during WWII.
For your historical knowledge, It was Maratha warlord Shivaji who first defeated the much bigger military of Islamic emperor Aurangzeb which in turn stopped expansion of Islam in India. In hand to hand combat, usually the braver soldiers prevail.
The issue here isn’t bravery, it’s the ability to produce war goods and deliver them to the front and turn those goods into firepower. China has a massive advantage in that area. India is very far behind.