It only depends on political will. Airtight isolation will be enough to solve Russia, let's say. On the level that "whoever has any diplomatic or trade relationship with Russia or does not accept the same policy, can't trade with anyone in the West", this policy will take days to "infect" entire world. Not being able to trade they will quickly descend to starvation, rampant disease and death. Then we can take refugees.

Also, well, if we were serious about it, we could throw in enough resources to defeat them like we did it with Soviet Union. Except not recognise any successor states this time: everyone out, with hands up, and that's it.

Doesn't work with North Korea, Venezuela or lots of other dictatorships around the world.

Regime change is hard. Creating a functioning, not corrupt state in the aftermath is harder.

Regime change is hard because maintaining any coherent regime needs will and capacity of the people. In case of Russia of course, it will not be the case. This is why Russia needs to be eradicated, not fixed. Population removed and replanted in many countries, so kids put into foreign schools, so language goes extinct in the next generation and whole "Russianness" thing ceases to exist.

That's the new North Korea scenario.

Well, not really. China continues to trade with North Korea prolonging it existence. If no one traded with Russia, things will be very different there.