lol that was some timing...
I still feel like your memory is too short... just 5 years ago Roma was languishing around the 6th-7th place in the league, and the Serie A victory in 2000 was soon followed by finishing 8th in the league. It is what it is, Roma is a selling club and will have some mediocre seasons until their finances finally improve.
And worry not, I think there's little chance of Zaniolo leaving, mostly because once the hype train slows down there won't be that many suitors (for the time being). What's his best position? He's supposedly an attacking midfielder... but he can't pass the ball at all. He's (no exaggeration) the worst passer in the league for his position. He does seem like a decent dribbler, he's very tall, and his finishing has been good (we'll have to see whether he can keep that up), which makes me wonder if he isn't miscast as a midfielder, worth exploring whether he'd be better as a pure striker. He better be because there's no way he'll be a star as a playmaker unless his passing drastically improves.
As for Ranieri... as long as he's just a caretaker until the end of the season it might not be that terrible. Roma's main issue the last 2 seasons has been that Di Francesco's high defensive line was totally incompatible with the defensive personnel at hand. Having to watch slow defenders like Fazio, Marcano and Cristante, plus a goalkeeper who absolutely never comes off the line in Olsen trying to play like that was frustrating. Ranieri might not be amazing but I would assume he'll improve the defense at the very least.