Just to give one data point I'm in Poland and I'm earning around 3500€ in a fully remote senior developer/engineer position working on AI tech in a company of around 1k employees. I'm one of the best paid people among my colleagues. The absolute top range job offers in this field in my country would be somewhere around 5000€ but that may be available only to a few developers in the entire 40 million country. I'm sure one could argue that one US engineer is worth 2+ polish engineers but I'm doubtful it's such a large difference. Quite the opposite in fact, I heard rumours that our engineers are quite valued internationally, once you get past the language barrier of course.

Just my 3 cents.