One good thing about the Russo-Ukrainian conflict is that it has made preparing for an attack on NATO practically impossible.

The Russians now know they cannot make any troop movements or deployments that will not be completely detected and understood by their intended targets.
Intelligence and surveillance technology is so capable, both state-operated and commercial, and is so detailed that a sneak attack like Hitler’s on the Soviet Union is impossible.
The European battlefield is like a chessboard, your opponent can clearly see what you are up to.

Not only is it impossible to stealthily prepare for aggression, it is now impossible to threaten hostilities unless you are actually preparing to do so. Even if the Russians are capable of correcting the deficiencies in their armed forces, they have lost the element of surprise (not to mention their credibility). And they will never be able to avoid the fear that any potential opponents will be able to make their assault very expensive, even if it is successful.

Of course, it works both ways. The Russians can easily see that the NATO forces across the border are not deployed or prepared for an assault, but can still be expected to be very capable in defense. We have no guarantee that the Slovakians or Poles or Czechs will be as ferocious as the Ukrainians, but the Russians will still have to assume they will, and prepare for it.
It complicates their planning. On the other hand, they have always known that there is no offensive threat from NATO, and even getting one in place would take months, if not years. But Russia has always known that, hasn’t it? Paranoia about NATO is an excuse, not a realistic fear of threat.

These considerations only apply in the case of a conventional war, nukes change everything, but that’s always been the case. From this day forward, if the Russians really want to invade the West (or vice-versa) the defenders will have plenty of warning. To a rational military planner, this can only mean war becomes much harder, less likely, and much less necessary. Putin is rational enough to understand this, but I believe he is also irrational enough that he now believes he has no choice but to do something really, really stupid. Like all bullies, he does not grasp that real courage lies in knowing sometimes you have to just cut your losses and back down.