They should negotiate to stop the mass murder going on.
What does that look like? A dissolution of the russian federation, complete Russian disarmament, ane the imprissonment of Vladimir Putin would stop this. Why isn't Russia offering that? Why aren't you suggesting that?
What do the people of Ukraine get from negotiating with Russia? Why should they trust Russia to uphold an agreement when Russia has already broken every agreement?
Give concrete answers or admit you don't have any.
What do you think, then? What is the realistic thing that Ukraine should negotiate for? And, again, what would make it so that Ukraine could trust that negotiation?