Your argument is a clear and sensible one. I think it would be good for very many people to rad it. At the same time, I feel that it falls short by ignoring Putin's nature and ambitions.

M view is that unless Putin & his forces are stopped now, the invasion of Ukraine will prove to be only an early step in a much longer and harmful battle.

As you say, "If we make the wrong choice countless more lives would (will) be lost."

However, my view is that such is inevitable. You are right about Putin, in as much as that he won't stop of his own accord, he will need to be stopped and if an effort to do so results in nuclear war then so be it.

A World in which megamlomaniac bullies can get away with whatever they wish is no place fo us to be, anyway.