My opinion is that I hope you go to €100M and actually get him. That tends not to be a great sign.
However, looking more in depth, if he makes the step up, it could work out well. You might finally have a creative left footed right winger, which then in turn would allow you to have Sancho on the left, where I think he should have been playing all the time. I believe this should give you better balance in attack.
Casimero should help provide balance and quality in midfield as well. More balance in midfield, more balance in attack, should make you a better team.
What these signings will mean for Utd, is anyone's guess. What I'm becoming more convinced of, is that as much as quality plays a big part, and the attitude / work rate of the players can often be the decisive factor. We've seen that no more evidenced than the last 2 Man Utd games.
For me, the challenge in front of Ten Hag, Tuchel, Conte & Arteta, is not so much about acquiring a good squad of players. The EPL is by far the richest league in the world, the big teams will buy big players, that's a given.
What sets Klopp & Peps teams apart is taking these players, and getting them to have their attitude, work rate etc spot on week after week after week. They believe in the their coach, in their team, and the demands that the coach places on them. Conte seems a master at this as well. Let's see how the others get on over the course of a season.