Does that scale neatly with salary? I would expect it not to, with things like benefits and other costs being relatively fixed regardless of salary

Is that 90k the "lower average"? In Ukraine? I find that very hard to believe. Even here in Czechia that would put you firmly in the top 5 %. I don't think I personally know more than 2 people who make anything like that, and one of them isn't even in IT.

That's right. 90k is the correct value for a mid-level (real, productive) developer across Europe. 40-50k is possible, but for entry-level positions.