As far as the nuke option goes, I do not think that Putin wants to or will pull the trigger on the destruction of Russia or the West. I do not think he is crazy enough to do that. Escalation creep is real and ongoing. it is very much a game of "chicken" that Putin has been encouraging. Prior to Feb 24th 2022, Putin had gotten away with all of his efforts with minimal effects from the West. The invasion changed the game completely and what had happened before was swept away and off the table. None of the prior events and accusations mattered any more. The very successful Ukrainian resistance emphasized that everything from the past decade no longer mattered. The NATO reaction is a clear reinforcement of that message. Whatever situations created by Minsk, Donbas, Crimea, etc. no longer apply. For Putin the invasion was "a bridge too far".