You undermine your own argument. Ukraine's admission was never going to happen anyway, and everyone knows it. Putin also knows it. So that isn't why he is invading.
Arguments about NATO membership or repressed Russian speaking minorities and anything else (you get different justifications for the war depending on where you are in the world...) are fig leafs to exploit people's existing opinions of particular parties (in your case, about the US throwing its weight around).
The reality is far simpler: Putin wants the Ukraine personally. His own private reasons are irrelevant. He wants it. And he has the will and capability to take it. And so he is doing so.
I'm going to pick one one part of your statement in particular:
> US and the EU should've realized the only way to defuse this situation was to negotiate
Putin wants Ukraine. Negotiation of any kind was never going to prevent this invasion, unless the concession surrendering without a fight and having Putin install a government of its choice.