Historically, heavily authoritarian leaders manage to find all sorts of “corruption” in their political enemies. Maybe it’s there and ignored until the people are a problem, or corpruption that is at odds with another corrupt interest, or sometimes just outright made up. Especially if the outcome is a lot of executions, that’s not generally a sign of integrity. See the French revolution where things came from a pretty sincere place but mass executions followed that weren’t exactly all justified or relevant to the situation.

You mention the US, and in a way that’s a decent example. Conveniently Trump administration found reason to use the FBI to raid a political enemy and has made rumblings about political enemies somehow deserving prosecution, inventing allegations as needed to make opposition look bad. So while they open the doors wide open for some corrupt billionaires to game the government to their advantage, they accuse others of various offenses including corruption. Pat of their efforts seem to be towards making it easier to carry out those legal threats.