There are a multiple reasons why that won't happen in the real world, including but not limited to: * The Ukrainian army is fighting ferociously to defend thei

There are a multiple reasons why that won't happen in the real world, including but not limited to: * The Ukrainian army is fighting ferociously to defend their land, not to invade another land. * The Ukrainian army should not stoop to the Russian level. They have no imperial delusions. * The west is generally against invasions of other countries, and this should cut both ways. The Ukrainian army won't get the same material support for a push deep into Russia. * Russia is not a small country. An invasion would take a lot of resources. More so than a defence of home ground. * While Russian use of nuclear weapons to invade would likely not be tolerated, use of nuclear weapons to defend against the same might be. It is a much more defensible action. * if the Russian defeat in Ukraine is decisive enough, the "Putin problem" will be taken care of within Russia.