I think he knows he entered a war he cannot win so I think he is looking for some sort of way out and a promise that Ukraine
will never join NATO. Which I think the Ukrainian side will reject. The whole 'meeting' is BS of course. Just buying time to refuel.
Ukraine could agree to not join NATO, the trouble is that both sides have a vastly different understanding of what that means. Putin likely wants to keep Russian troops in the country and/or have a puppet government. Ukrainians would likely want some sort of security guarantee but not by Russia, which really doesn't leave a lot of options that aren't related to NATO. Maybe China can step in here

Ukraine should agree not to join NATO, and then join NATO, and then tell Russia that reports of them joining NATO isn't true. It's just western war mongering.