If he is given the opportunity to play more, I'm sure he will give his best for Barcelona, but the question is whether Hansi Flick will give Rashford a starting spot because, as far as I know, Barcelona's front line is already filled with Lamine Yamal, Rapinha, and Lewandowski. But I think Rashford is only used as a rotation option when Barcelona faces average clubs in the La Liga competition later. Well, when Rashford is given such an opportunity, it should be an opportunity for him to show his best so that management is interested in making him permanent.
I have not watched Rashford perform yet on Barcelona but I have an optimistic mindset of his positive change in the club because he is going to do what he has never done before in Manchester United, people are really thinking otherwise about him but what they did not no is that Manchester United is usually not a club to say that a player will never do better if they leave the team to another club. What Manchester United could not do for him Barcelona will do it better for Rashford because he will be starting from the champions League and even if they did not win it there is certainty of another new season champions League.