Well, he was not found guilty of any of the accusations by the Supreme Court of India. As an Indian that is more than enough proof. Also Modi cannot be compared to Putin or Xi.
So if no one is safe from corruption just by becoming PM for one or more terms, then we should abolish all positions of power? That would be a really stupid thing to do. If you can't trust any system including the Supreme Court of the land, move to a country you find perfect (no such country exist, no country has perfect systems, if everything were transparent and if there were no propaganda, things would be easy to understand).