Unfortunately while there are many alternative approaches of equal or greater value than the Shanghai rankings, approaches using straight citation analysis really aren't among them. 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 really glaring flaws (their criteria for designating "core journals," for example). This is one of the most interesting topics in meta-academics right now, and as is 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.

The rankings are determined using six objective indicators of academic and research excellence. Key metrics include the number of alumni and staff winning Nobel Prizes and Fields Medals, alongside a university's per capita academic performance.

Publication records also play a critical role in the evaluation. The agency tracks the number of articles published in Nature and Science, the volume of articles indexed in the Web of Science's Science Citation Index-Expanded and Social Sciences Citation Index, and the number of Highly Cited Researchers identified by Clarivate.

That criteria is weighed at 40% of the ranking.

The number of US universities that switched to "research university" and the pressure on all academic staff to publish publish publish probably has something to do with the rankings...

Is the ranking rigged? No, it's published by a Chinese university. I'm saying US universities are gaming it.

Is doesn't judge quality of published work, just quantity of published works and number citations. GIGO? It's hard to tell on a short term.

From Wikipedia: "The ranking has been criticised for "relying too much on award factors" thus undermining the importance of quality of instruction and humanities."

In a report from April 2009, J-C. Billaut, D. Bouyssou and Ph. Vincke analyse how the ARWU works, using their insights as specialists of Multiple Criteria Decision Making (MCDM). Their main conclusions are that the criteria used are not relevant; that the aggregation methodology has a number of major problems; and that insufficient attention has been paid to fundamental choices of criteria.[27]

The ARWU researchers themselves, N.C. Liu and Y. Cheng, think that the quality of universities cannot be precisely measured by mere numbers and any ranking must be controversial. They suggest that university and college rankings should be used with caution and their methodologies must be understood clearly before reporting or using the results. ARWU has been criticised by the European Commission as well as some EU member states for "favour[ing] Anglo-Saxon higher education institutions". For instance, ARWU is repeatedly criticised in France, where it triggers an annual controversy, focusing on its ill-adapted character to the French academic system[28][29] and the unreasonable weight given to research often performed decades ago.[30] It is also criticised in France for its use as a motivation for merging universities into larger ones.[31]

There's more criticism. Take the ranking with a cup of salt.