I still very much believe in Rashford.
He's out of form at the moment, yes, but so is the team as a whole. Let's not pretend we've played particularly well since the Chelsea game on the opening day of the season, even in our two recent wins.
In 2018/2019 Rashford scored 10 PL goals, despite playing 50 % of the season out of position in a woefully dysfunctional team and another 25 % injured. During the remaining 25 % when Ole first came in Rashford was absolutely flying and everyone was saying how good he was.
Based on that, you'd have to think Rashford can get 20 league goals in a season where the team is playing well as a whole and he is starting centrally. But even if he doesn't he's still a very useful player in many other ways. Does Firmino get 20 league goals a season for Liverpool? No, yet they won the CL with him as an integral part of their team. It's all about finding the best roles for each player and getting the most out of the squad as a whole. Also, I think football might be moving away from the 30-40 goals a season strikers anyway. I think the most PL goals any player scored last season was 22. Rashford still got half of that despite the factors I mentioned above.
He's got great pace, movement, dedication, work rate and many other attributes. Particularly, he's very good at stretching the opposition's defense and running onto through balls from the likes of Pogba. Yes, there's also a lot of room for improvement with regards to his box-play etc.
He is playing too many matches and should be rested. Personally I wouldn't have started him yesterday and instead played Lingard as a false 9. So I would do a bit of rotation and then bring Rashford back to play centrally together with Martial in the following line-up, where he would have the added responsibility of occasionally drifting out wide right in order to provide width there:
--------Martial Rashford--------
James----------------------------
---Pogba---Fred---McTominay---
Shaw - Maguire - Lindelöf - AWB
--------------DDG-----------------
I think that is how you get he best out of him. Allow him to play to his strengths and stop focusing too much on his finishing right now, we have other players who can share that responsibility.