Putin is just being depicted that way by the Western media, and this can be taken back or at least rectified within a couple of months. Even more so, if the media would look more carefully at the events shortly before the invasion, what the Selenski did in the Ukraine and how the Biden administration was involved in this military build up and pressure on Russia, as well as the Ukrainian opposition. Of course, this won't happen now, it might never happen, but its possible.
And if the Ukrainians don't take negotiations seriously, their country will be completely ruined for decades and they won't be any more free or happier than they could be if making peace.
For diplomacy its not too late, unless one side has won all and won't accept any compromise. In this case, there are at least weeks to come in which this is not the case. And the Ukrainians better negotiate now than in 2 weeks, because Kherson has fallen. The Russians forced the Ukrainian forces to leave the civilians out of Mariupol, finally, the storm of the city will start soon, I guess within a week it will fall, then its Kharkiv. This will probably need 2 weeks, then the big pincer will crush the Ukrainian main forces, the whole Donbas front will collapse. There will thousands and thousands of Ukrainian dead and taken prisoners.
The only reason they are holding right now is that they have used the buildings of these major cities and the civilian inhabitants to slow the Russians down. But once these major plugs are gone, they will be helpless in the open, this will be a big run for the Dneper for what remains of the Western UAF.
I think Selenski understood by now that no one wants a nuclear war for his invented heroic tale or for taking away Crimea from the Russians by force. He will step down from his arrogant position, one by one, the closer the pincer movement comes, the closer the collapse of the Western front, the more he will give in or has to be replaced. That's what will happen, that's what should happen, as soon as possible. Or does anyone want the Russians to steamroll over all Russian cities like they had to in the East, in cities like Mariupol which will just a bunch of rubble soon? Or that Russia crumbles with its nuclear missiles and becomes an unpredictable mess? Or the worst case scenario, that we head for a nuclear third World War?
What are the options? It was known from the start. All this useless, one sided hate-propaganda only makes peace more difficult to achieve. The only innocent people are the soldiers and civilians which being thrown into this mess, from both sides, but definitely not the Selenski regime, not the Putin regime, not the Biden regime. They are all guilty for going for that escalation unwilling to compromise. Totally unnecessary and predictable, like predicted by all serious analysts in the last year: Don't go for confrontation, try to negotiate, give Russia options, don't push for the NATO membership, arms race in Donbas, a purged Ukraine unwilling to compromise with Russia. Don't do that, stop it, it will end in a catastrophy.
But Biden, unlike Trump, just proceeded in pushing Ukraine into a war.