He built the Summer Palace in St. Petersburg in emulation of the European palaces he visited on his tour of Europe. But unlike European palaces, in the Summer Palace he installed a torture chamber, in which he personally tortured then murdered his own wife. He seems to have enjoyed torture and murder.
This is the model that Putin so admires.
I don't know that it's yet possible to ascribe any war-crimes to Putin personally. The crimes that I've heard tell of are of the kind that might be carried out by low-morale troops in any army.
Of course, the Russian army in Ukraine necesssarily have low morale; they've been ordered to attack and kill people that their own leader has said are their "brothers".
Low morale in the Russian armed forces is a persistent problem; in WWII Russian assaults, Russian machine guns were positioned in the rear, to kill any Russians that thought to fall back. It's not surprising that in the fall of Berlin, there was widespread looting and rape by Russian soldiers.
All soldiers behave like this, to a greater or lesser extent. But this Russian army has been engaged in city-flattening, rape and murder to a shocking extent.
Personally, I'm not inclined to forgive. But that's not my call; I'm not Ukrainian.
Thing is, Putin has boxed himself in; he's said publicly that Ukraine is not a thing, that so-called Ukrainians are in fact Russians, and that he aspires to a Peter-the-Great-style Russian empire stretching from Vladivostok to the Baltic.
The only "off-ramp" I can see being halfway-acceptable to Putin would be for Ukraine to surrender their claims to Donbas and Crimea, in exchange for Russian security "assurances". Even that would make Putin look weak; he's declared that one his goals is to "demilitarise" Ukraine. To do that he would have to conquer the whole of Ukraine.
So any promise by Putin to accept a proffered "off-ramp" would be seen with a very jaundiced eye by Balkan, Central European and Baltic states. And by me, actually.
I'm no warmonger; far from it, I've been mostly a pacifist most of my life. But any "off-ramp" plans would either be unacceptable to Putin, or they would lead to a new war.
I'm afraid it looks pretty bad.