It is looking for the moment like Ukraine is containing Russian troops NW of Kyiv and rolling them back to the NE. Russia is making headway degrading resistance in the SE on the coast.
If Russia flattens the SE enough to communicate deeper into Ukraine, they can potentially change momentum and disrupt what Ukraine is doing around Kyiv. NATO would then need to seriously consider stepping in more directly.
On the other hand, if Ukraine can bring enough to bear to dislodge and destroy the Russian force NW of Kyiv before Russia makes very much progress in the SE Ukraine may be able to pressure and disrupt the Russians there.