Russia has consistently signaled that they have no intention of accepting even the current frontline as a negotiating point, as far as recently passed Russian laws are concerned, large areas of currently Ukraininan controlled territory like the city of Kerson are part of the Russian Federation and any agreement that gave them up would be illegal under Russian law.

Moreover, given how well appeasement worked for them in 2014, there is little public support for such a strategy in Ukraine, even if Russia’s stated core goal wasn’t to prevent the possibility of Ukraine joining any defensive agreement that would make a further invasion difficult.

If Russia comes to the negotiating table, it will either be because a large scale collapse is inevitable on either side, or because they’ve run out of North Korean shells at a time where their opponent is gaining access to increasingly more modern weapon systems. The Soviet Stockpile is massive, but you can only empty it once.