EPL is a domestic league that the clubs are use to the game pattern of their opponents, and that makes it easy to understand themselves in the long run. Europa is filled with clubs from various leagues making it hard for them to understand their game patterns. This is why clubs that you don't expect do win this league. Amorim needs to understand that it's easier to achieve success in Europa than EPL.
Your concluding statement sounded confusing except you were trying to put it the other way and had a typo arrangement, nevertheless big European teas who's experienced enough still have that edge over the other small tea.s who may want to go luck dependent at some point because they probably may lack the experience and may even not have the capacity to win the league technically. Manchester United even in their poor state is yet to show any terrible performance in the Europa so for me Amorim tactics will be n added advantage and will literally help them in the long run to to building that advantage over others and an opportunity to win the League title at the end of the day.