There is ZERO chance that this proposal is true. Firstly, Russia would NEVER allow Crimea to be ruled even partially by Ukraine. That would not only be unworkable, and put Russia's Black Sea Fleet in jeopardy, but such a move would go against the will of the Crimean people, who feel themselves to be fiercely Russian and who voted overwhelmingly to join the Russian Federation in 2015. Proposing to "share" the peninsula with Ukraine is simply not workable.
Likewise, to turn Crimea into a "demilitarised territory" would go against CENTURIES of Russian military and naval tradition: Sevastopol has been the home of Russia's Black Sea Fleet since 1783.
Moreover, Russia would NEVER allow Ukraine to control Kherson, because Crimea depends on Kherson - and the Nova Kakhovka Dam - for most of its electricity and almost ALL of its fresh water. In fact, it was always a strategic goal of Ukraine to BLOW UP the Nova Kakhovka Dam in order to destroy the economy and living conditions in Crimea.
I wrote about all this in my article:
"The TRUE story of the Russian dam that blew up in Ukraine"
And finally, Russia would never allow the Zaporizhzhia Nuclear Power Station to fall into Ukrainian hands - because Donetsk and other Russian territories rely on the ZNPP for power.
The areas mentioned in this article are all part of Russia; they were formerly incorporated into the Russian Federation in September 2022. There is no way for Putin to negotiate them away. It would take an act of the Duma to do so, and that will never happen.