(freestyle) wrestling kind of died out in the ex-soviet bloc over the last few decades and just became a kavkaz thing (and increasingly, just a dagestani thing). I looked through the records and so far as I can tell only one ethnic Russian has ever won a medal in freestyle competing for Russia (they had good guys back in the Soviet era though). And that was a bronze, in the 1990s. If Dagestan wasn't part of Russia, Russia would be nobodies in wrestling today. And other eastern bloc countries are increasingly just Dagestani mercs wrestling for them at the world level too.
EuroRussians mostly seem to do sambo/judo, and Greco Roman is the most popular wrestling in central/eastern europe, but Greco is kind of a limited and sucky style by itself IMO. Some of those 'strikers' you mentioned to have some greco roots I believe (Pavlovich) but it doesn't seem to translate to being an 'MMA wrestler'. I guess the reason there have been less and less elite grapplers from that area outside Dagestan these days is because it's a damn tough lifestyle and most euro-russians & other slavs would just rather work normal jobs than be about that life (Fedor, the most famous sambo/judo guy, grew up in the impoverished 90s but since that era there don't seem to be many guys like that). 'murican collegate system seems quite unique in its ability to get ppl 'embracing the grind' of wrestling in an otherwise rich country.