Your enemy doesn't sue for peace when they're winning. When they hold all the strategic objectives. That's when they push for unconditional surrender, not offer favourable peace concessions.
You can't just skip ahead to the peace deal because you think it would be better. Your enemy doesn't care what's better for you, and no amount of clever arguments and well-assembled slide decks is going to change that. Nor is politely asking for a different negotiator.