No one wants to go on history as the leader that wiped out half of his country population.
This doesn't mean that it won't happen, but not on a premeditated and rational way. Accidents and crazy people do exist.
Finland and Sweden know this. Russia won't dare ever to attack a NATO country. But NATO also doesn't dare to do more than send arms and little more to Ukraine.
Russia military fiasco on Ukraine only confirmed that an army runs on its country economy and Russia just don't have capacity to have a big modern army, it has the economy of Spain.
This is the stupidity of Putin's revanchist. Now it is as if the Russian Empire is rapidly approaching its death, and this is good.