Here’s where I think you are right: Perhaps allowing Finland into NATO is too confrontational and inflammatory.
Here’s where I think you are wrong: Containing aggression of nuclear powers when they misbehave is MORE important than if they are not nuclear powers. Which is why we, and the others, are doing the right thing by supporting Ukraine from this invasion. Putin used everything except the weather to try to justify this invasion. Arguing as if NATO expansion was the real reason is a stretch.
Lastly, from a realpolitik standpoint, it certainly seems correct to let the Ukrainians teach the Russians a lesson.