The limiting number for a "Russia goes bananas and decides to steamroll into Portugal" event, based on what we've seen in the invasion of Ukraine so far, seems to not be the number of soldiers but the amount of functional equipment.
Russian production numbers sound good if you ignore that most of them refer to stored Cold War era equipment being reactivated. Their main and most successful staple has been artillery and that mostly worked because it could be fired from the safety of being on a side of the border NATO pretty much told Ukraine not to cross - for a time. It also seems like the "saber rattling" Russia did in the lead-up to the invasion by positioning military around the Ukranian border was less of an intimidation tactic and more of a necessary part of the process.
I'm not saying Russia couldn't do a lot more damage in an all-out war into the West even without involving nuclear weapons (which already assumes European countries with nuclear weapons or the US wouldn't use them either). But based on the underwhelming performance of the Russian military relative to its supposed numbers, I don't think Russia could have pulled off the kind of Blitzkrieg you're envisioning, let alone once supply lines become a problem. Especially if you consider that the plan for the invasion of Ukraine clearly was built around a surprise attack on Kyiv, which failed spectacularly because the terrain and weather meant the tanks had to drive slowly in a line and somehow Russia didn't bother providing infantry support.
Russian production numbers sound good if you ignore that most of them refer to stored Cold War era equipment being reactivated. Their main and most successful staple has been artillery and that mostly worked because it could be fired from the safety of being on a side of the border NATO pretty much told Ukraine not to cross - for a time. It also seems like the "saber rattling" Russia did in the lead-up to the invasion by positioning military around the Ukranian border was less of an intimidation tactic and more of a necessary part of the process.
I'm not saying Russia couldn't do a lot more damage in an all-out war into the West even without involving nuclear weapons (which already assumes European countries with nuclear weapons or the US wouldn't use them either). But based on the underwhelming performance of the Russian military relative to its supposed numbers, I don't think Russia could have pulled off the kind of Blitzkrieg you're envisioning, let alone once supply lines become a problem. Especially if you consider that the plan for the invasion of Ukraine clearly was built around a surprise attack on Kyiv, which failed spectacularly because the terrain and weather meant the tanks had to drive slowly in a line and somehow Russia didn't bother providing infantry support.