his pragmatic side will win the argument and agree to the cease fire
I don't see how Putin can agree to a ceasefire, which may eventually turn into something more permanent - while Ukraine continues to occupy areas of Kursk Oblast.
Right now, things look like they're developing very quickly, and that the Ukrainians may be ejected within say a week. Zelensky already confirmed today that there is a withdrawal underway.
If it takes a week - then I can see how the Kremlin is able to request a week to "study the ceasefire proposal" (or some other excuse) - and then agree to it only once the Ukrainians have conclusively lost their negotiation leverage with Kursk.
But if the Ukrainians continue to hold on to pieces of Kursk for longer than a week or thereabouts - then Russia cannot agree to a ceasefire on the timeline being pushed by Rubio and Trump. The Ukrainians will then start blaming us for not playing ball, and complaining to the Americans that we are bad faith negotiators.
The other issue with this ceasefire is that it includes a resumption of military aid to Ukraine. This doesn't smell good... We give the Ukrainians a month to replenish their manpower and rearm - just when they are at their weakest in this three year long war?
Supplies of weapons to Ukraine should be paused for the duration of the ceasefire. If Russia violates it, then they can resume, and perhaps in larger volumes than previously. This would represent the stick for Russia, and the pause the carrot.