Well, assuming your project really takes off and you do have $1M, you could live (half a year +1 day) in country 1, and the remaining (half a year -1 day) in your country each year. You'd pay what, 10-15k per year in extra rent in the second residence? Probably acceptable if you have 1M.

That way you're "clean" when it comes to taxes, and don't have the downside of leaving everything behind. Easier said than done of course.

(Implicit assumption you're the boss of your thing, so you can work remotely as you want.)

As others said, getting new friends in a new place (especially abroad) when you're, say, over 30, is really tough.