It's a head-fake. They are not bargaining in good faith. Still lots of shelling around Kyiv.
NATO should be pouring weapons into Ukraine, including S300s.

Putin is seeking to achieve multiple objectives in this war. On a broader, strategic scale is the revival of the Russian Empire, which would be achieved with the fall of Kyiv and installation of a Russian friendly regime. He’s failing there.

A more tactical goal is securing a land bridge to Crimea, achieved by seizing territory in Eastern Ukraine.  I think Putin is backing off his larger objective goal (for now), and focusing on locking in gains in the East.