They would've known about God 3,000 years ago. No, Chinese and Native Americans and etc did not ignore him. Abraham was of a pagan land when he first encountered God.

In any case, it was definitely communicated across the world. If you're picking a specific point in time when first contact was established according to a specific tradition, that might raise a question of why first contract there and in that way. But we in 2025 have the hindsight of seeing what happened globally after that and spread it did.

I don't think it is a coincidence that specific groups of people received revelation the way they did, when considering things like the quality of their oral and scribed history. Would you pick a region of people who don't know how to write and barely know how to talk, or a region of people who are highly skilled in both?