Has anyone ever considered alternate Earths where convergence point was keyed to Russian settlement of Siberia? The closest setting I can think of at the moment that would be centered on alternate Siberia is Jacek Dukaj's Ice, but it uses Tunguska Event as the divergence point.
What would the world would like if the Russia did not expand and colonize into Siberia?
Maybe Khanate Of Sibir would resist Russian intrusion, revitalized into efficient state becoming a barrier limiting eastern expansion of Russia? It could force Russia to expand into west and south, pushing it into even more conflicts with Polish-Lithuanian Commonwealth, which could diverge into timelines where Russia prevails, timelines with tenuous balance between those two forces and timelines where Commonwealth wins over Russia. Any of this timelines would involve a domino effect reshaping further history of Europe and in long term history of the world — but those would be more of subjects for alternate histories of Commonwealth.
Another possible path would be less expansive Russia, either growing into stable state not relying on expansion and Siberian resources — would it remain stable or fell into stagnation and degeneration, however?
Back to Siberia for now: how would it develop without Russian settlement? Probably slowly... The primary influx (does this word actually mean what I think it means in this context? yes, it is) of people was Russian colonization, especially with exiles and prisoners. Without them there would be much less cities and no railway present. Khanate Of Sibir could expand and colonize it, but it would probably lack the Russian reserves of people for settling eastern regions. Without Russian claiming the land, Siberia could be colonized from the east by Chinese, Manchurian and possibly later Japanese settlers — either dissidents and exiles escaping chocking grasp of strictly conservative rulers of the East or deliberate colonization of more progressive (and/or expansive governments). Maybe it could lead to revival of often forgotten states and peoples that were subjugated and suppressed by Mongols few hundreds of years earlier?
Two another scenarios based on different history of Siberian settlement:
Russia starts colonization of Siberia providing settlers, both volunteers and forced but at some point of the colonization there is revolution, military or economic that frees Siberia from Russian control creating one or more independent countries — United States Of Siberia?
And the second one involves Władysław Vasa becoming Russian Tsar and Polish king (which in our timeline failed because of his father meddling). With personal union between Russia and Polish-Lithuanian Commonwealth there would be distinct possibility of Russian culture being influenced by Commonwealth's religious and cultural tolerance of early XVII century and spread it into east... But it might be more appropriate for Alternate Earths: Vasa Dominions post(s).