I went to graduate school with an Indian woman whose family had been Christian for 500 years, I think through the Portuguese, but during the time I knew her she became a Protestant.

There were Nestorian Christians in China since at least the year 635. Christianity was exterminated and reestablished in China more than once.

The Greek successor kingdoms in India, Pakistan, and Afghanistan were instrumental in spreading Buddhism to China. Bodhidharma is sometimes described as a “blue-eyed barbarian” from the West. People got around more than we think.

https://en.wikipedia.org/wiki/Syro-Malabar_Church

https://en.wikipedia.org/wiki/Portuguese_India

https://www.thecentersquare.com/national/article_ef050358-9d5a-432b-addf-a9e899490668.html

My wife’s best friend (and my friend too) is a Catholic from the Bangalore region, with Portuguese ancestry going back maybe 600 years. She is the youngest in a large family, with several siblings who live here in America and several siblings (and uncounted cousins, aunts, uncles, nieces, nephews, etc., plus mother and father) who live in India. She was born and raised in India and has said that she never experienced problems with Hindus. As a child, growing up, she met and knew Mother Teresa, who would sometimes visit their home. She loves India and visits it as often as circumstances allow but is very firmly American, totally assimilated (lives in Chicago) with a Midwestern accent — but able to do a spot-on English-Hindu accent after being plied with a few glasses of wine. I get the impression from her that there is nothing “cultural” to being a native born Indian Christian, i.e. that there is Christian culture per se; rather, you are an Indian who happens to be a Christian, period. So, no conflict with Hindus, or with Sikhs, Parsees, Jains, whatever. She’s married to a Chicago born Irishman who can also do the Anglo-Indian accent, perfectly and hilariously (but respectfully, of course).