All countries distancing themselves from Russia and aligning with the EU have managed to reduce corruption. It's a winning formula, so will very likely happen with Ukraine too after the corrupting Russian influence is eradicated.

Poland, while not entirely corruption-free, has managed very well after the transition from Russian-dominated communism. For reasons I still do not understand, organized crime was rooted out in the 90s, and gambling restricted to almost nothingness (gambling is always tied to organized crime).

Not perfect, but doing pretty well, and the effects can be seen.

Former Yugoslavia. From what I hear from my parents' generation, you couldn't do anything or it would take a serious amount of time without bakshish, today it' pretty frowned upon, at least in the EU countries. Serbia and Bosnia are a different game...