Buying a lot of new players does not mean becoming better, ten Hag did it before, in the previous off-season they also bought a lot of new players, but despite this they had an even worse season. New players need time to adapt, to play with the team, all this takes time, and competitors will get ahead. I think that nothing will change for Manchester United, their main goal at the end of the season will be to get into the top 4, but this may not be easy, because there are teams that are progressing better like Aston Villa, which you mentioned, and Tottenham, Newcastle and Manchester United will fight for the Europa League, that's what I think.
Sometimes buying new players will actually help the club even if it is about performance because the concentration of the management to be on the players both the old and the once's about to be signed. And you will notice that when it comes to some particular player they will want to do everything possible just to get that player to the club this is to show how important so players can be to the club just because of what having him will add to the club. And the case of Chelsea and new players is now the issue of player, if not other clubs also have new players and they are performing well they don't take time to blend but I think this will be for some players but even if it is taking time for the player to blend it should not be taking much time. And if they should make top four then they tried because, with this there condition it won't be easy we all know their current condition better Manchester United than Chelsea now. Aston villa is one of the toughest club that almost had unbeaten in their home and deprived arsenal from winning the premier league, they should consider how to battle this clubs before aiming too four.