It's not a fantasy at all, which is of course why you have no greater retort than flinging ad hominem responses.
Russia's poorly organized, poorly funded, poorly trained military will be hyper exposed as they go fully into Ukraine (it already is). We also have the intel on the ground in Ukraine to help us out, we can maul Russia's tanks, artillery and mechanized forces and wipe out their supply lines, trapping their ground forces inside Ukraine with no supplies (aka they're dead). Russia can't project effectively outside of their borders when confronted with vastly superior NATO air power, so they won't be able to provide cover or resupply for their soldiers trapped in Ukraine. Their hardware will be wiped out. We can dismember their air force at the border as needed. And it'll be Ukrainians killing the Russian soldiers inside of Ukraine, not NATO soldiers. What else does Russia have?
They'd have one fall back: I'm gunna nuke you, I'm gunna nuke everyone, I'm gunna nuke the moon. [insert Putin turned Gollum snarl here] Bullshit. It's not sovereign Russian territory and they're not going to kill everyone in Russia for it.
I'd be glad to see them beaten back, but you're living a fantasy.