The Russian military is geared towards both defensive and offensive operations. They're highly mobile, and sometimes they move and strike much faster than NATO can even react. In just days, they moved more than 100,000 troops towards the Ukraine border. And that was just a year ago. Their VDV is made for offensive operations. Their equipment and vehicles are made to strike fast. Much of the vehicles are wheeled, not tracked.
And I think it's ridiculous to believe that they pose zero threat. Especially after Crimea and Eastern Ukraine. Now the Belarus threat against the Polish and Lithuanian borders. Russia is running drills with VDV and long range bombers along the NATO borders. Why? Because they want to link Belarus with Kaliningrad and cut off the Baltic states from mainland NATO territory.
Back on topic, Spain is rarely taking part in any offensive NATO missions. The Eurofighter still provides air to ground capability. They might not need the F-35 except for the assault ship Juan Carlos I.
I'm curious how you see this threat. Do you see large army groups rolling through Poland, or just "insurgence" taking a chunk of Lithuania, or what?
They poke and probe to find out what works. A common tactic they are using is spetsnaz of various backgrounds as tourists in rented vehicles operating inside the Baltic states, Poland, Norway (and Svalbard), Sweden and likely Finland. They do recon as well as limited missions against infrastructure. In Sweden they destroyed an electrical transformer. In Norway they use GPS jammers. There's a lot of stuff like that going on. A few years ago Swedish intelligence found out the Russians were very interested in Gotland. The threat was real, and Sweden sent mechanized infantry to the island to protect it.
After Crimea and Eastern Ukraine, NATO has built up forces in the Baltic states, including air protection and QRF. They're there for a reason.
Any military mission is a valuation of what you gain and what you lose. If an offensive mission costs too much economically, political capital, equipment or losses of own soldiers, they won't do it.
When it comes to military strategy, there's always a balance between symmetric or asymmetric warfare. If the enemy has tanks, planes and missiles, the best strategy could be an asymmetric response with militia, local insurgency and sabotage. And vice versa.
So it's impossible to accurately predict what's going to happen. It all boils down to making an attack as costly as possible for the enemy.