I’m not sure that the fact that Hot Courses bought the Complete University Guide is super important, after all USNWR is a private media company with no particular expertise in education other then creating the rankings? Whether a particular ranking is valid for you goes to whether you like the methodology used and value universities similarly to those conducting the ranking. Here is a link to the Complete University Guide methodology (which utilizes data in the public domain). https://www.thecompleteuniversityguide.co.uk/league-tables/methodology/. The Guardian explains it’s methodology here: https://www.theguardian.com/education/2016/may/23/methodology-behind-the-guardian-university-guide-2017. A portion (not all) of that ranking uses the National Student Survey scores.