They're starting a new cycle. Yesterday the oldest player on pitch was Marquinhos (29) and the average age of the players on the field was below 24 apparently (Zaïre-Emery is 17 so drags it down but still). They got S.Ramos, Messi and Neymar out. I think the back four is significantly upgraded (though Lucas Hernandez injury record may be a recurring issue), Ugarte may be the midfield engine that team lacked for many seasons, the front line is a lot less scintillating glamour wise but Mbappé (?), Dembélé, Ramos, Asensio is way, way above average. Kang In Lee is there, possibly Kolo Muani ? Next year Xavi Simons is back from his loan so maybe there will be a good spot for him to take in that team. Front unit seems more than sorted.
If Mbappé goes, even if replaced by Kolo-Muani, the team definitely slip a notch down. The biggest unknown otherwise is Verratti, but if he stays he could maybe do a job in the rotation. If he leaves they need a replacement.
They just won convincingly against the team that finished 2nd last year.
I think they very much still target the CL and the objective is at least to reach QFs. Maybe could do with a couple of big recruits next year to round it up but that's a solid core that should be good for the next 3 seasons (defense will maybe need new blood by that point).