Although Choupo-Moting's contract finishes next season if I'm not wrong but still I don't think he's going to be the right fit for Manchester United. So far even with Bayern Munich, he has not been that much consistent even after the departure of Robert Lewandowski.
Another thing is that he is a mediocre-level striker which a team like Manchester United might not like. They need a striker who can score on a regular basis and Choupo-Moting is not something like that. I think they should try to buy some other player instead of him.
it's true that Choupo Moting is the target of Manchester United in this transfer season window, Manchester United wants Choupo Moting to become a new sticker in their squad. so far it seems that there has been no official offer made by manchester united for bayern munich for his interest in their stickers. Even though Choupo Moting is 33 years old, he seems to have rediscovered his best form this season, he can be a good player to fill the position left by Ronaldo. therefore we will enjoy how this situation of interest will work in reaping an agreement on both sides.
Zidane is an intelligent man and a very good coach. He has high standards and would never take over a weak team because he wants to win trophies. There are other coaches who are different in character and would accept challenges even with weaker teams, but I don't rate Zidane that way. He would only take over a top European club like City, Bayern or Real.
As you said, maybe Zidane will not accept a job from a weak team for his coaching career in the next era. Indeed, Zidane desire to train France has run aground after Deschamps got a new contract extension to handle France. Therefore I think Zidane will continue to wait until the big teams call him to be their coach after this season is over. Both PSG, Chelsea and Juventus are the clubs that will offer him a contract if the coaches who train these three clubs cannot make a major contribution to the progress of the club this season.