It's quite strange that Man United wants Joselu, who in fact is no longer young. What I know is that Man United really wants to make big changes, but Joselu shouldn't be part of that plan because he is not the right signing for long term plans. I think Man United just took advantage of the opportunity because they could get Joselu at a fairly cheap price as a backup for Rasmus Hojlund. Obviously, it's a gamble, even though it's cheap, but if in the end, he can't make a contribution then it will still be considered a wasted signing.
I also think it wouldn't be wise to recruit Joselu for a long-term goal, even though he just had an explosive match helping Real reach the Champion League final. In terms of the performance of the whole season at Real, Joselu is not too outstanding, he often plays in the reserve position and he only plays at a normal level. He is 34 years old, only has a few years left to play at his peak, and Joselu's latest move also shows that he wants to stay at Real until the end of his career.
With Man Utd's current situation, I think they should prioritize signing contracts with potential young players for the team's long-term goals. If you have more financial potential, they can recruit a few stars who can revive the team in the next 1 to 2 seasons.
True, it is better for them to focus on young players only to build a better foundation for the long term. Because if they focus on older players then it will probably only last 2 to 3 seasons, whereas they have to always take part in competitions and of course they always have to have a very prepared squad every season. Joselu can be relied on in some matches, but overall he is not as outstanding as you say. Of all the matches he played, he recorded 15 goals with Real Madrid.
Apart from that, they also have to be able to evaluate their current coach, because I see something wrong with Erik Ten Hag. Manchester United is in a downturn right now, they are having a really hard time getting up. As a big club like them, of course this is something that is very unfortunate, because they do not show that they are a big club in the Premier League.