I'm sure Man United will develop much more under coach Erik Ten Hag. the battle between Barcelona and Manchester United still leaves time, at least Man United will prepare their troops to face Barcelona in the playoffs later. and I think Barcelona will do the same. So, let's see how these two teams develop when they play their matches in the domestic league.
Both Ten Hag and Xavi are building their squads to win the Europa League title. They still have enough time to remove the weaknesses within the party and strengthen the party. But if the players are not able to consistently perform well, the team's problems will not be solved. However, both teams have strong squads. And they have a lot of talented star players. As their performance is not consistent, no definite prediction can be made about this match.
I agree that they are going to end up with a good team by the end of the season. They are both trying to win Europa but they are both trying to win the title in their own domestic league as well which is why it's so easy for them to fight for the cup at the same time.
When a team is the leader of their league, they are given a bit more money to build a team so that they could keep winning, and this allows them to have a deeper bench, which means they could play those bench players which are not too bad on league games against easier opponents and then their starters on the europa as well. Barcelona has a bit of trouble with United though, that is going to be tough, Arsenal has easier path.
Manchester united has proved that they are a very strong team,ETH has done so much to revive the club to this present form. I can't say who will win the match between them and Barca,but I know the stronger side will finally win. Barca has a good team which makes the match to be a tough one and unpredictable for now. There is still time and we will be able to figure out which club will win the match,based on their performance when it is getting close to the match day. I just hope Casemiro will be playing on that day.