As a new coach in a new club, you have to try some formations to find a best one for players you have. Ten Hag is just doing that job and the temporary result is acceptable that allows him to continue his trials.
The defeat against Aston Villa confirms a fact that Manchester United need to have some supplements from transfer market. If they want to finish in top four and aim at higher targets next season, they should start a good preparation since this season.
Speaking of Sancho, it's true lately he's always been in the limelight because of the mess he makes and always blunders where he goes when playing on the wing. Therefore, it is better if Erik Ten Hag puts Garnacho to have an option. Because so far Garnacho has only paid more attention, but if it was honed I think it would be quite ideal to give that position rather than Sancho. Furthermore, Rashford also needs to learn a lot because he did not do much in the match against Aston Villa. Therefore, there is Antony who is more hardworking in his position. Erik Ten Hag will continue to do a lot of trial formations that are considered effective but with the remaining time, it also doesn't seem like enough to keep playing losing.