Whe loan to Barcelona, he has showed impressive performance, even then he managed to become Xavi mainstay in every game they played, but unfortunately his poor relationship with Atletico fans and coaches actually made him have to leave for Chelsea as one of the recruitment requirements for Connor Gallagher at that time, at the beginning of the season he was actually able to compete in the Chelsea first squad but slowly he began to be eliminated, especially now that he has an injury that makes it difficult for him to get a place in the Chelsea first squad again later, so indeed moving to another team (Aston Villa) which can guarantee a place in first squad and more playing time is certainly a good option for his career at this time.
He had a good career at Atletico Madrid but because of some problems he faced, he was not well received by the fans so he was loaned.
There were many teams that approached him at that time but he preferred to play as a loan player at Barcelona so that at that time he also made a big contribution when Xavi became a coach.
Injuries are a big enough problem and it is still quite difficult for him to avoid and staying with Chelsea will make it difficult for him to get a main place in the team.
If Aston Villa are interested in signing him then I am sure that would be a much better place for him to play and not getting enough first team football could make his career even more uncertain.