Rashford is a roster of young stars so he will have to go through new experiences on the pitch and hard training to become a professional player, so it is natural to criticize recent performances as last season's performances did not live up to expectations even though Rashford was not included in the starting line-up in every game. but he is first choice if Ronaldo is absent or replaced so Rashford can be counted on to improve and I also believe he will work for that.
Rashford will have to work harder to reach his peak as a striker, he still has the chance to become one of the best strikers in the Premier League but has not been able to maximize that so far. Last season he had 25 chances to prove his worth, but unfortunately he was only able to contribute 4 goals. It was not as expected, and next season Ten Hag is expected to handle it well.
I'm sure Rashford has better ability if he wants to train hard. This was probably another matter he had to think about if he wanted to become one of the best. Rashford seems keen to stay at Manchester United and is struggling to prove his worth under his new coach.