Once you work out the history of a European country in the last couple of hundred years, you then find that there is another layer before that, and so on back to the Tower of Babel. No wonder Australians and Americans can’t understand what European conflicts are about.
In the case of Russia, they go back to the early Slavs in about 600 BC. One theory is that there was one original Slavic race at that time which spoke “proto Baltic/Slavic”. But as far as I know, there is no evidence for any of it, it is just a theory which might explain later events.
(interestingly, the location of the proposed early Slavs is on the banks of the Pripyet river in northern Ukraine. That is the location of the Chernobyl reactors, which makes archeological investigations difficult at the moment).
There is another theory (which is rubbished by the establishment) that there was no such thing as early Slavs or an original Slavic language. This theory says that different tribes at that time interacted with each other and by that process created the various Slavic tribes and languages. The parallel used to explain this is “what are the origins of the Americans in the USA? Did the pilgrim fathers, French, Spanish and English who settled in north America think of themselves as Americans when they left home?”)
Maybe the other way of thinking about all this is that the shape of European countries is determined by wars and not much else. What is happening in Ukraine at the moment is just another example of what has happened for millenia in Europe. Because of the war, there will be created a Ukrainian identity and universal use of its language.
At least America had a revolution and civil war, Australia has missed out on all this. We had to base our identity on beating England at cricket. But recent immigrants aren’t interested in cricket, so they will have to think of something else to create a national identity.