If they were foolish enough to try to attack NATO facilities in say Poland it would trigger Article 5. They know this and would not do it.
They will and are targeting the supply lines (hence the attacks on railway infrastructure). This "war" is a complete clusterfukk. They are only now trying to target weapons and fuel supplies. Compare it to the Gulf War when the allies took out transport infrastructure, communications and supplies from day one. It is almost certain that most Ukrainian supplies are now either in hardened shelters and/or distributed away from pre war stores. Their best chance to stop the flow of supplies is to target the transport infrastructure. Three months in and they are just starting to do it. Reportedly they are still having logistics problems of their own despite having shifted to concentrate on the Donbas.
The last thing the Russian military could cope with would be a sky full of NATO fighters and supported by NATO air defences. Their Black Sea fleet would also be very vulnerable on day one.
Russia is at war with Ukraine, why would Ukraine not strike targets in Russia if it is able to? Russia is not at war with Poland so they cannot "legitimately" attack NATO targets there without triggering Article 5.