I think that the nazis will start causing terror all across Europe is a very likely scenario. They will feel betrayed by the west, and they've already been establishing links with western nazis all around Europe. Millions of people fled to Europe from Ukraine, and there certainly were many nazis amongst them. Also worth keeping in mind that a huge number of weapons sent to Ukraine ends up going missing, and I'm sure a lot of these weapons have already made their way to terror cells across Europe. The west has unleashed a monster in Ukraine, and it's inevitably going to bite the hand that's been feeding it.