Huh? They aren't giving up anything unless they can be forced to give it up. But they're winning the war and there is nothing anyone can do about it, not unless NATO tropps enter Ukraine and fight Russia directly. And that would likely lead to a nuclear war.

Since Russia cannot be defeated by Ukraine alone and We don't want a nuclear war for involving NATO, we must negotiate to save what can be saved in Ukraine. If there is no negotiation, Russia will destroy Ukraine's army and defeat Ukraine militarily, then impose non-negotiable terms.