Ukraine

Those that have a choice, and those that commit such atrocities, I agree, they don't deserve pity. But many will have some dignity left, and once in battle have little realistic chance to "just stop". We must be very careful not to vilify people solely based on their membership in a group. Each one deserves to be judged individually, when possible.

Kill them if they attack, or enable an attack, yes (this includes logistics far behind the lines: legitimate targets!), because it's a matter of survival of you, your comrades, and your country, but still recognise them as humans. Once going down the path of dehumanising the enemy, Ukraine will lose the moral high ground, which is paramount in maintaining the right to receive help from the civilised world.

I don't believe in "destroying Russia", besides its practical impossibility. Unlike Nazi Germany, Russia does have the ultimate doomsday weapon, and might use it if really threatened existentially (to paraphrase some propagandists: "If there is no place for Russia in this world, why should there be a world?"). That said, I have absolutely no idea how to deal with Russia. None. Every conceivable solution is terrible.