The 4th position this season is in the hands of Arsenal and I'm not sure Manchester United and Tottenham will manage to overtake Arsenal until the end of the season.
If I have to choose one potential team that can take over the fourth position from Arsenal, I would choose Tottenham, not Machester United.
Arsenal's good form can be expected to stay safe in the 4th position at the moment, they have a few points advantage over Manchester United and Tottenham and Arsenal also have 1 game in hand. So it will be good to keep thinking Arsenal will be safe in 4th place this season.
Arsenal in surprise of all, have managed their performance good and long enough in this season. Now the season is going to the end and with advantage they currently have and their latest form, I don't see how Arsenal will lose it.
West Ham, Tottenham and Manchester United will compete for the 5th place as Europa League contestants. Maybe Manchester United will take this ticket later even though their performance is not consistent.
I think Tottenham will finish in the fifth position, and the sixth position will belong to Manchester United. It's not good for Ten Hag to take over the club like this but he has no choice. He only can hope now but in my opinion, if Manchester United have to play in Europa League next season, it would be great for him. Because there will be less pressure on him so he will be able to build up the club gradually.