Only a fool thinks that this is about Ukrainian ego. Ukrainians are fighting for their very survival not just as a nation but their personal lives. Putin from day one admitted that this war is genocidal in nature. The elite Russians don’t feel that Ukrainians have a right to live or that Ukrainian has a right to exist.
Bluff or not it really doesn’t matter because you cannot negotiate with terrorists or at gunpoint with a suicidal moron. If you give in an inch you will only encourage further aggressions. The only way to obtain lasting peace is to finish off the idea once and for all that nations can invade and take territory from their neighbors regardless of their possession of nuclear weapons.