Most young people I know use Facebook for groups (local like a school or city), events , and chat. IMO Facebook is shooting all of these feet off with the algorithmic newsfeed and spinning off messenger.
Snap however is used constantly to keep up with peers. Haven't met a single person that uses instagram's stories, even though its usage numbers tell another story.
It really might just be my age/location/privlege bubble, but it consistently baffles me that Facebook keeps growing at such a faster speed than snap.
I asked my younger siblings and none of them nor their friends have facebooks, besides the one in college. They all have snap and insta, and spend ~2X time on snap than insta. Most text communication is snap or SMS.