The situation is almost entirely focused on the south of Pangong Lake from the banks of finger 4's immediate southern counterpart to Reqin. India in the past always held the mountains right to the east of this southern region and they have considerably more build up and supply apparently. Focus where you are strong and attack where they are weak, using Tibetan "frontier forces". Rather clever textbook tactics but then that also means expected moves.
Since it's a predictable move to be honest so if the CCP and PLA were truly caught by surprise (assuming Indian ingress is true) then they are just simply too incompetent. Better to just back down if this is the case. More likely this is controlled and the expectation was always that the Indians will look for paths of least resistance. If this is expected and allowed to eventuate, then there may be escalation from PLA since this is the natural motivation for allowing such obvious gaps to exist and ingress to occur. Fireworks to be expected if so. If no fireworks, seems like CCP and PLA were just caught with their pants down.