Vietnam might be a much weaker country compared to India, but the principle still stands. A layer of the Indian economy is resilient, but high growth depends on foreign investment. There, they are quite vulnerable. At this point, foreign currency reserve is so low that they are just enough to pay the interest of their large foreign debt for three years. The source of their foreign currency are mainly in three sources.
1. repatriation from abroad by workers. This has been cut due to Covid.
2. exports, the Indian IT service industry is not growing like it use to anymore. India produces very little goods to sell abroad, mainly minerals.
3. investments from abroad.
The IT industry is fragile. It depends on power and communication cables which could be cut in a war. New Deli is 300 km from the Chinese border. a few missiles can destroy enough power plants to turn it dark for months. Same with oil refineries.
War is also not good for investments from abroad. There are enough groups like the Kashmiris and the Maoists that China just have to provide some weapons and training to see bombs going off in all big cities, and cables cut. That investment was already waning anyways as the Indians do not allow foreign money to make a profit. Just ask Walmart how much money they lost trying to invest into India. The Chinese may ask for tech transfer, but they never not allow foreign corporations to make a profit.
It is not hard to see the Indian economy growing at 0-3% or lower as long as the war is being fought. While I would not call this as collapse, but it nevertheless means stagnation while the rest of the world moving on. Since they cannot even make ammo, there will be a giant sucking sound for their precious foreign reserve to buy weapons that are used/destroyed/broke during the war. This competes directly with buying stuff to maintain their factories.
The sadder thing is, it does not have to be this way, but they pick this path.