it was around the year 880 when Oleg of Novgorod, a Varangian brigand, captured Kiev, which is generally considered the beginning of the Kievan Rus, i.e. the beginning of Russia.
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Nope.
Russia did not become Russia until Peter the “Great” decided that Moscovia was an inadequate name for his county’s greatness, and stole the name ‘Rus’ from the then long vanished Kivian Rus’ Empire which was, on modern maps, Ukraine.
You can have your opinion but it’s not shared, especially in Russia.
Nobody in Russia believes that it started with Pyotr.
Here’s a little link:
https://www.worldhistory.org/Kievan_Rus/
Not a bad description. Notice the map: it encompasses what is now Western Russia. The map changed many times in the ensuing centuries, as it always has in Europe.
And modern Ukrains is a subset of that, as any Pole or Lithuanian or ByeloRussian or Latvian person will tell you. The border wars continue, which is all that’s going on now.
But ultimately the confederation of all those places did start with the Varangian (Rus) Rurikid kingdom. Novgorod was the Northern part and Kiev was the Southern terminus.
People in Russia regard Putin as a Varangian for instance. Some have argued that he’s South Slav himself, and his family line may have such genetics. But he’s rather Swedish in looks, and so he is regarded as such: definitely isn’t a Black Russian.
Of course we could go deeper and claim that modern Ukraina is a German development, but that’s a longer story.
It’s not as simplistic as you claim.