it seems loss of power and control is what this war is about. And NATO expansion really does cause Russia loss of power and control.

So ok, yes, it seems a plausible factor in the decision to invade.

But doesn't Ukraine get a vote in this? If they are freely choosing to shift westward (which they have progressively been doing), don't they have the right to do this?

so even if you are 100% percent right (which seems unlikely) ... even in that case is it not really a valid or moral justification for invasion.

sometimes we cannot offer as much as the other guy, and so we loose the negotiation. Does not give us the right to grab the gun.

(btw, I am not trying to paint the USA as the "good guy" I am just saying that even if all of what you say is true, Russia is still the bad guy here.)