You forgot to include the potnetial impact on the other side of Europe. A rearmed Germany will certainly activate a bout of national diarrhoea in France! As and when Putin is pushed out of Ukraine -with or without German help - or a peace treaty is made, there will be shrill demands from Paris that Germany disarm. If the Germans don't comply -and there is no reason for them to do so -the EU will split down the middle.

Remember that the original reason for the EU as a concept was "To keep the Russian out and the Germans down". Not succeeding in either right now!

BTW, King Charles has no authority to take a national stance against Putin, whatever his personal views might be.. Only Parliament can do that.