I am 100% certain that Unai Emery is miles and miles better than Erik Tan Hag without a doubt, the comparison isn't even close in my mind, I think it's quite clear that Villa being higher up than United by that much margin proves that Unia Emery is an elite level manager.
I hear that United is interested in Tuchel, which wouldn't be that bad, I do not think that Tuchel would be able to turn this team around that easily, I think it is going to take some time, but I feel like it is not going to be that impossible neither. We will see them do better I think, well usually new managers at United do very well on their first season, and do very badly on their second season, which I think will be the case for United and if they hire Tuchel as well, great first year, terrible second year.
I don't think, coach is the challenge of Manchester united, because Erik Ten Hag really performed well in my own observation in this premier league competition that just ended few weeks ago, and if more chance can be giving to Erik Ten Hag in the next season, I think he will try more than this next season. I disagree with you by saying Aston villa coach is more talented or better than Manchester united coach, I believe you can still remember the position of Manchester united and Aston villa last two seasons that made Manchester united to ended up in a fourth position and Aston Villa ended up 7th or 10th position. I know Thomas Tuchel is an experience coach that know how to improve a team and I believe he will do well if Manchester united Management want to change Erik Ten Hag, because Thomas Tuchel helped Bayern Munich to get to semi final in the champion league competition in this season.