NATO's attitude towards direct participation in the war is eloquently evident from its assessment of the attack on a drone over the Black Sea, the fall of Rossian missiles on the territory of NATO states, and much more.
Meanwhile, it is obvious that you can call yourself the first or second army of the world, but if you happen to find yourself in a real war, your army will be incapable and will make fatal mistakes one after another, as we saw in the example of the Rossian army during the first year of a large-scale war.
It is possible to possess enormous, surpassing resources of the enemy, but these resources are easily lost as a result of a lack of combat skills. And the proof of this is the fact of the transformation of many kilometers of columns of military equipment into burning scrap metal, the transformation of hundreds of servicemen into piles of torn bodies by a rocket strike within seconds.
It is hardly possible to speak with confidence about any army as the first, second, third army of the world, if this army did not take part in a serious war.
This also applies to NATO. In addition, it is not very smart not to take the opportunity to debug the interaction of troops in a real war, to check combat readiness.
These may not be entire units, but a group of individual servicemen of different specialties: tankers, pilots, gunners, Air Defense specialists. Something similar to the transfer of experience to our military specialists from the West.
Many will say that NATO's participation will create the threat of a world war, that Rossia will be able to declare the participation of NATO troops in the war. But don't we know that Rossia has long been at war, according to both Putin and his mouthpieces, with NATO?