Comment by _heimdall
Russia has an estimated 1.5 million troops and plenty of equipment. They have seemed to still be very lacking in military logistics, which is crucial, but they also haven't seemed to be throwing everything they have at Ukraine.
I'd strongly recommend you not underestimate Russian ability by assuming Ukraine is the best they could do. That doesn't mean they are going to invade further into Europe, but we're talking about military size and deterrence here.
I'm sure Russia can do more, e.g. they have not enacted martial law and forced conscription. What I'm saying is that the current level of deterrent seems enough given what we now know about Russia's military might.
NATO-without-USA has more aircraft, tanks, and watercrafts than Russia. Less stored ammo for sure, and probably not as effective, but on the other hand: nukes.