I also agree with you that Man United should not ignore the EPL even though they are very ambitious to be the best club in the UEL because after all the EPL is the most important competition because even if Man United wins the UEL title if Man United is relegated then they cannot appear in the EPL next season moreover with Man United's current condition I doubt they can win the UEL title because the competition is almost as tight as the UCL.
Manchester United must still care about the remaining matches in the EPL because after all Manchester United must survive there without having to experience relegation even though it is quite difficult to be in a much better position because now Manchester United is still outside the top ten in the EPL standings. While in the UEL, the level of competition will also still be quite difficult over time especially when they are in the round of 16 to the quarter-finals because in rounds like that all teams will try to perform better.