Then your statement has no meaning. If everything and everyone is corrupt, then no one is corrupt, everyone's just normal. But yes, then the answer is "how corrupt". And, objectively and empirically, Protestant churches are less corrupt than their peers.
That wouldn’t matter to me. No skin in the race but my comment still stands they are all corrupt because people are inherently corrupt. The same as I don’t believe the Bible is the true word of God as it has been translated over and over again by man to suit their needs and will continue to be until the end of time.
The upside to this dilemma is humans also have the ability to know or learn right from wrong. So the power of choice is great.
The other great upside is most Christians believe if you are truly repentant for your sins you will be forgiven which is a light at the end of the tunnel for them.
Christianity at its Core is awesome. Implemented in today’s current society it has a lot of flaws but still achieves many great things for many people.
Still, inevitably it is not as pure as people hope it would be.