It's sad to see those Ukrainian marines surrendering in Mariupol, posted above, I dread to think what will happen to them now, assuming they are actually Ukrainian.
Sky has been showing a mass movement of people from cities & surrounding areas, just outside of the current Russian controlled areas, heading north & west, they have seen what has happened to the likes of Mariupol, the war crimes committed in the north, and have decided to get the hell out before it's too late. The humanitarian disaster we have seen so far is about to get so much worst, both in terms of refugees, and war crimes in the east & south.
The EU is firmly split over further sanctions, especially over gas & oil, the Polish president is lashing out at both France & Germany, we have the UK, US and many EU leaders openly calling Putin a war criminal now.
Putin has got himself in a mess, is intent on grabbing as much of the east & south as he can, and destroying everything in his path, the Ukrainians did well in resisting the Russians in the north and forcing their retreat, but are struggling in the east & south. The peace talk are basically over, not that anyone could trust anything Putin says or agrees too anyway, although at least China has stepped in calling for peace.
Putin is going to keep pushing, and Ukraine is going to struggle even more against increasing Russian resources heading to the east & south, something needs to change, in order to push Putin back, ideally without NATO engaging with the Russians directly. The only answer I can see to that, as I posted yesterday, is for 'peace-keepers' to move into areas where there's no fighting to assist with both the humanitarian disaster and war crime investigations, freeing up Ukrainian resources, Putin will not like it, but I doubt he will/can react to such an operation.
It would be happening outside of the war zone, it probably wouldn't be a full NATO operation, just certain countries, there would be no logic in Putin then attacking those countries as (a) they are still not engaging directly with the Russians, and (b) to do so would drag the rest of NATO into it. And, for those reasons, he would not carry out any nuclear threat, the principle of M.A.D. that has stood up so well & for so long, still stands today.