> is there any country an immigrant can move to, and better their lives as well as the locals' life/economy?

The United States.

> It seems the world is turning hostile to immigration in general - or maybe it is just the impression I get from the media?

The world is turning hostile to immigration because the media (and social media sites) highlight and repeat the bad anecdotes, while barely mentioning the actual data showing positive outcomes.

People are turning on immigrants because the pie has been shrinking for decades.

What data suggests there is a positive outcome for the first world in integrating with the third world? Because my data suggests we're enthusiastically recreating the conditions that led to the Yugoslav civil wars.

And even you know it; I saw your other comment before you deleted it. You are well aware that there is a tipping point, and expressed disappointment that natives are resistant to the path that leads to it. It's like you want there to be ethnic violence.