Of course the number of single Russian girls residing in US or Canada is incomparable with the number of Ukrainian or Russian girls who are still in Ukraine or Russia.
So for a woman from Ukraine who is already in US, Canada or Europe we have about 6 men interested, on the other hand for a Western man who comes to meet in Ukraine we have 6 women, the difference is 36 (!!) times.
So if the woman is already in your country it’s for her to choose: the man should not be older than she (3-5 years of difference at most), live in a big city, have an income above average, have a house etc.
On the other hand single Russian girls who are in Ukraine will accept a difference of age up to 15-20 years, will be more interested in your personality because it is obvious that with a rather modest income in US or Europe you exceed the income of an average Ukrainian man. And since the number of single Russian girls in Ukraine is much higher, you are guaranteed that the woman you meet will be very beautiful, well educated, younger than you and most essential, she will have traditional family values.
Another thing is the budget of dating and marraige is higher if you meet a woman who lives in your country because you will go out with her a few years before she compares you with other candidates and makes her choice.
If you meet a woman in Ukraine everything happens much faster because women know what they want and if she falls in love with you the rest of things will happen very quickly.