Interesting..............
Think of moving the Bronze Age back 10 to 15 thousand years and have it around the equator. The only remaining temperate area. The ending of the ice age flooded these people out. Moved the shoreline in, etc. There are some “sophisticated looking” temples and other structures that are close to shore but underwater in the Indian ocean plus I think I have read about some in Indonesia, etc. The one’s in India seem to predate the coming of Aryan civilization
Of course its a seismically active area so they could still post-date the last glaciation. Also I don’t seel ancient people short in their cleverness when it comes to building, doing, voyaging, what eve rthey feel they need to do!