. . . Japan shuns immigration . . .
No they don't. I've lived and worked there for more than 15 years. My brother and his wife and son are permanent residents there.
Japan can be welcoming to immigration . . . they just have a high bar. They don't take jag-offs from anywhere who just wants to live off the taxpayers.
Their immigration system is fairly simple: if you are determined to be a net benefit to Japanese society, then welcome. Otherwise, stay out or go home. Not all that tough to understand, really.
Most sane countries operate on comparable systems. Even relatively sparsely populated countries like Canada and New Zealand.
I read somewhere that either New Zealand or Australia won't even take you if you are over 40. (I suspect that imported wealth would override that.)