Largely I expect because somebody else suggested the ceasefire first.
Agree he’s potentially going ‘all in’ with Israel OR the ‘big beautiful thing that the world has never seen’ is not only is he going to stop the Iranians from developing their nuclear weapons, he’s going to take out the regime altogether and ‘free’ the people of Iran.
There’s clearly no dice with Putin who won’t be told anything, by anyone, ever, so he can’t rescue the people of Ukraine. So maybe he’ll be the saviour of Iran instead by taking down their regime. I absolutely dread to think how but you can be sure that whatever he’s planning will likely be in his own interest.