By the time of writing this post, there are no clear answers to what exactly has happened
Is such scenario possible?
Russia and the US made a deal.
Russia gets a large part of Ukraine in exchange for Assad's withdrawal.
US, Israel and Turkey will share Syrian territory among themselves
The Russian decision makers are naive (dumb) when it comes to believing their Western 'partners' but even such naivety (dumbness) has limits, those limits were breached in the Minsk 1 and 2 Accords with Germany and France,
I disregard such an agreement unless Putin is racing Biden into dementia.