Unfortunately while there are many alternative approaches of equal or greater value than the Shanghai rankings, citation analysis really isn’t a great alternative. It’s one of the most criticized methodologies for some very good reasons and, while Leiden does better than most at controlling for things like citation mills, their methodology has some real flaws (their criteria for designating “core journals,” for example). This is one of the most interesting topics in meta-academics right now, and as can be shown in this somewhat infamous paper from fudan university the reason is that impact is a great deal more complicated than any simple metric can represent.