Rashford can't afford to be lazy if he wants to become a key player in the Barcelona squad, and he must also be able to work with the existing players in the squad. If he continues to show his ego during any match, he may not get more minutes in the Barcelona team and won't be signed permanently by Barcelona after his loan period ends. I also want to see how Rashford adapts to the other players at Barcelona, as they were generally good players, judging by their performances last season.
Becoming a key player for Barcelona might be difficult, as there are other names who might shine brighter. however, he can try to stay in the starting lineup so he doesn't end up on the bench. he should be able to do that, given his talent and under flick coaching, he might get the game he's been hoping for, just like Antony, who moved to Real Betis and immediately impressed, and perhaps Rashford could do the same.