I think a material difference between Iraq (v2 anyway) and Ukraine is that they can keep doing the "well Russia was the aggressor" thing indefinitely even if the reality is more complicated.
also yes obviously some libs are still stubborn about Iraq, the worst ones, but for the most part its generally agreed that the Iraq War was a bad thing.
It's a gradient and blurred line that further blurs over time as "intelligence guys" start doing special operations and assassinations of political and military targets, and the "advisors" are launching recon drones and coordinating the Ukrainian military. Oh, not to mention all the "recently retired" military "mercenaries" driving the tanks.
Eventually US soldiers do occupy held positions as well, as seen in Syria where there are thousands of literal US troops occupying the country yet almost every American would say we never invaded Syria if you ask them. Huh weird, if you never invaded how did thousands of your troops set up bases in a nation you were not invited into? If you never invaded, why are you launching cruise missiles and drone strikes into Syrian territory? This American fiction about "boots on the ground" is a Liberal delusion to assuage the cognitive dissonance they have about being a bloodthirsty world-conquering military empire.
Then after the fact, if Liberals ever acknowledge their complicity in an invasion, it's framed as "the US got pulled, unwilling, into a quagmire" as if that wasn't the full intention the entire time and they didn't get pulled but were pushed in by the US government and MIC - first as advisors, then as intel guys, then as mercenaries, then the drone strikes as "anti-terrorism" operations, then as "peace-keepers" in a coalition force. It's a smooth gradient, there is no wall.