Yes you are right, at Manchester United he did not get a team that was called solid earlier, in fact I think the opposite. Even so, he can still be the top scorer. Isn't this proof that even when he is in a bad team he can still do that, especially if he joins a solid team like Bayern Munich I'm sure he will be able to perform optimally.
Well, exactly, no matter if he can be the top scorer in that club but if seen from the club entirely, Ronaldo may not be able to perform optimally in the club. However there is still uncertainty about Ronaldo in that club, so there is still a chance for him to leave the club.
Sebastian Haller has joined Borussia Dortmund and is back to Bundesliga after a fairly decent run with Eintracht Frankfurt and after being kinda poor with West ham. Revitalized his career at Ajax with 32 goals in 50 appearances. With much more attacking prowess that Borussia brings. He should thrive there.
He has worked very well in Ajax and becomes the main striker for that club. This is good progress for Borussia Dortmund to have him as well to replace Hallaand's position. Although this of course will not be as good as Hallaand butat least Sebastien Haller is also a great striker