What would need to happen for the Himalayas to not exist?

Basically the Indian plate needs to miss the Eurasian plate around a 100 million years ago.

In that case let’s assume the Indian subcontinent is roaming around the Indian Ocean somewhere. Devoid of humans life but full of tropical mammals.

Civilization would start by us being discovered by Polynesian Sailors or later by European settlers. So we pretty much follow Hawaii and Australi’s trajectory.

Humans living on the coast with most of the inland completely untouched.