If you think Munich isn't corrupt, you should ask a Münchner - hell, their airport is named after a corrupt politician. [0]
But as a few Germans have put it to me - sure, there's corruption here, but at least it still gets things built unlike _Italian_ corruption.
Which is an... ...interesting point of view.
[0]: https://en.wikipedia.org/wiki/Franz_Josef_Strauss
As for London, they built an entire industry around hiding money for oligarchs who stole it from their own countries. Maybe it's technically legal, but it's morally corrupt AF.
As a German I'll say that even acknowledging there is a corruption problem (while still being unwilling to change it and not voting for the parties that let corruption fester) puts them a good step ahead of all those thinking there's no real corruption.
No studies, personal impressions, so I might well be wrong and maybe they all know but don't care. No majority that cares either way.