Summary: Russia doesn't want to go into any negotiations with Ukraine having any leverage. So Russia will take this back before they talk.
Just some random thoughts:
You have 1,400 miles of border. Not every area is battle space. Kursk was a good move by the Ukraine. Find a weak spot and take the initiative at least in that area for a while. The Russians played it smart too. They didn't drop everything and focus on Kursk. They kept their eye on what their true objective is and dealt with Kursk as they could without sacrificing their offensive operations elsewhere.
What I find amazing in this conflict is how modern tech regards battlefield surveillance, artillery and air power (difficult to create concentration), drones, have turned the battle-space into something reminiscent of WWI, fighting in trenches spread out over long fronts.
Ukraine had hoped to capture a nuckear plant and nuclear weapons just beyond their Kursk graveyard... they got heldup in Suzja and then lied about why they went there.
The AFU could not advance, nor retreat so they settled into holding their own self inflicted killzone.