Isn't Russia demanding the full scope of zap and kher too? Even the parts they haven't yet occupied?
If so I think he's overreaching and overestimating Trump's eagerness to strike a deal.
They've said they
want everything east of the Dnipro, but their conditions set for these peace talks are hinged on those points and build off the istanbul talks. Ie no NATO, no nukes, no foreign troops, and accepting separatist regions. Except then the regions could have been autonomous but formally in Ukraine, now they demand them formally in Russia. Zaporizhzhia and Kherson aren't written as firmly into Russia's constitution as the eastern lands they actually occupy, so there's definitely wiggle room for Russia to accept peace on terms they can spin as consistent with their own laws and claims. But that comes down to haggling over where the actual borders would land. Putin has said today that he wants a buffer zone, which basically makes it a buffer zone in a buffer state
Kursk falling today seems like it actually removes the biggest impediment to peace. Russia had no reason to agree to a ceasefire when they would have to trade for lands they were about to take on the battlefield. Now they can just sweep UA forces back to the border and there's no negotiation to be had over Russian lands, only Ukrainian