Which app store is used by Russians in the face of Google's sanctions?
Ordinary. It doesn't even require registration and doesn't drive you into its ecosystem like Google. Of course not all the apps of the world are here, but the vast majority are. And there is very little low-grade crap, unlike Google. It is also pre-installed by law in all phones sold in Russia.
https://www.rustore.ru/

One more interesting fact: Alt Linux has a mobile copy (Alt Mobile) and supposedly it is a “backup” in case Andorid for some reason becomes unavailable for delivery with devices in Russia.
This information is for those who are interested.
https://altmobile.org/download/