In my opinion, the Premier League is too competitive for Antony. In La Liga, he was able to adapt quickly, and it can be said that he is starting to rediscover his best form. Therefore, leaving Manchester United seems to be a better option next season. Besides that, Ruben Amorim seems he would not mind releasing Antony permanently.
No, Antony has no problem with EPL, he has a problem with Man United. I'm sure Antony can adapt well in EPL if he gets a proper team. You must know that many players suddenly perform worse when they join Man United. Now, Antony proves his quality again after he is loaned to Real Betis. No doubt that it is the best choice to leave Man United.
Regardless of whether it is Manchester United or the EPL, sometimes for players from Latin America, especially Brazil, it seems that the EPL is not an easy place to get glory because not a few Brazilian players fail because it is a different situation where the fast style of the EPL and high tension is actually not too suitable for Brazilian players who sometimes prioritize games with high skill and technique. Especially when talking about Manchester United, which is currently as good as any player when they are at Manchester United, the possibility of them getting a decline in performance is very pronounced and possible to happen.
At the moment he is slowly gaining momentum back at Betis but later for Antony this can be a lesson that choosing the right club and suitable according to his style on the field is also an important thing to think about.