if he stops trying going for goal then his only purpose is to supply Rashford and Martial which is a total waste of his talent and he wont develop as a natural forward but as a limited winger, that's not his natural game.
So player can't score goals and add creativity and assists to his game? He should bd selfish when he needs to be in good situations, I agree, but he should also stop trying shots when he will obviously end up blocked and pass to a teammate who is obviously in better position. That happened so many times in his last few games, even Cavani was annoyed against Everton if I can remember well.
And also, you just said you want us to develop one individual player over our teamplay, which is more upseting that anything I said. Rashford creates double than Greenwood does even if he can be greedy at times. Rashford can sometimes take ridiculous shots from outside the box but he is hardly ever greedy in the penalty box when he has teammate in better position. There is a reason their goalscoring stats is similar, and in the creativity and assists Rashford beats him easily.