Yesterday Zelensky said the goal is to establish a buffer zone in Kursk to prevent Russia opening another front in Ukraine.
Perhaps this idea I put forward here: >>/52318/ is right and they essentially testing how Russia reacts when attacked. And it is also an exercise, a learning opportunity for Russia to polish their defense plans and actions.
https://www.defensenews.com/global/europe/2024/08/19/zelenskyy-envisions-buffer-zone-as-ukraine-pushes-into-kursk-region/