the point here is that after Mongol period Russia started to collide in 15xx with Polish–Lithuanian Commonwealth with the issue culminating in Polish invasion of 1610 resulting in Moscow capture and putting up Polish Prince as Tsar. It came pretty close to Russia just becoming a satellite province/vassal state of Polish–Lithuanian Commonwealth. During the 16xx Swedish Empire is rising and is going south and east and firmly cutting Russia from Baltic Sea and taking a bunch of North West territories. In the second half of 16xx the slowing down Russia was no match for modern Sweden. Without Peter the Great's modernization (suppose his sister Sophia's coup succeeded) of Russia and winning the war with Sweden as a result, Russia would have most probably lost a lot of territories (including core territories like Novgorod and Moscow regions) in the next few decades to Sweden and Poland and, instead of becoming Russian Empire, would be reduced to some small dukedom(s) on the Eastern edges of Europe, and with probable forced Catholicization it would basically cease to exist as a familiar Russian state.