Well, this is a fantasy. Putin's purpose in entering Ukraine was to force Ukraine and the West to the negotiating table - and it worked. The Russians and Ukrainians had agreed a draft peace deal in Istanbul in early April.
Then the West told Zelensky not to sign, and so Putin's plan went up in smoke. He finally recognised the 4 oblasts as part of Russia in September 2022. That was the point at which he had given up all hope of negotiating any kind of a peace deal. He finally realised that he has no reliable partner for negotiations.
So now it is a war that Russia will fight "to the last Ukrainian".
Shame.