The idea is rotation, but Cavani is not happy with just that. He is the type to push to play. He has rivalry with Neymar, then Icardi.
For all the bad press against Icardi, he get on well with other players, like Neymar, Mbappe. Cavani is very competitive, but also the type that thinks he's better than he really is.
Edit: Cavani had rivalry with Zlatan too. And by all the rumor, is one of the few players that Zlatan holds grudge for.
https://en.as.com/en/2020/05/07/football/1588839328_356466.html