I'm thinking along similar lines - he must have been supported by some powerful people from the shadows. Not sure if it's the FSB and president though, they bot

I'm thinking along similar lines - he must have been supported by some powerful people from the shadows. Not sure if it's the FSB and president though, they both came out against Wagner. Maybe a faction within FSB though? Maybe some oligarchs? As for why he withdraw, I don't think it was because he got a sweet deal, but rather that his backers wavered in their support and giving him an offer of exile was the only favor they were capable of granting him.