People from may countries travel the world, emigrates and all that.

With about 140M Russians in Russia alone, it isn't surprising we see them going to other countries, and see a lot of them.
Especially the state Russia is in these days, or better said, last decades.
Any nation produces good as well as not so good people.

Its great, you have some Russian friends. Perhaps this helps to pick up their language a bit?

Question: Why so many non-natives in your neighbourhood? Immigrants flocking together? Locals not liking the immigrants to much, or at least, not that much to share a residential door, or street? Or simply, because immigrants and expats drive the prices up way too much?

NJOY the international character of Vietnam! And the Russian food! yes, indeed, I tried a few dishes. Been to Russia myself a few times in the further past, kinda like the 00's of this millennium/century, about 2 decades ago. Moscow, always Moscow. Never St Petersburg.