Regarding the OP’s question about LAC rankings, I agree that the T20 and T50 LACs have a lot more in common than the rankings would suggest, particularly if you pull out the US service academies which are listed as LACs in the US News. There will be difference in resources based on endowments and alumni giving, some schools may have newer and spiffier labs, arts facilities, or athletic facilities. They may have different cultures and focus, but an engaged student can get an excellent education and have an excellent undergrad experience at any of them. So no, the different rankings between say, Wellesley and Bryn Mawr, or Hamilton and Dickinson, should not persuade a student that Wellesley or Hamilton is “worth it” but not Bryn Mawr or Dickinson.
When we started the LAC search for my kid a number of years ago, my professor spouse was skeptical about the education offered at LACs in the T20-50 range, my kid’s target range since he needed substantial merit to make the finances work. Since I’m both stubborn and a born-researcher, I dove in to examine the metrics he considers meaningful – the faculty at LACs. For him, the quality of the professor’s Ph.D. training is what matters – are they serious academics who had been trained by top thinkers in their field? So I had charts showing where faculty in specific departments relevant to my spouse and kid, at a range of LACs, earned their Ph.D. We could do this because we know a lot more than the typical family about graduate education, things like, Pitt and Rutgers are leading Philosophy programs, and Cincinnati is a top Classical Archaeology program. Guess what? The faculty at the top 10 LACs were not a different level of “illustrious” than at the Top 20, or Top 30 or Top 50. The focus on professional training of the faculty may not be a meaningful metric for a lot of families, but for our family, it showed that the “playing field” was a lot more level across the T50 on a metric that mattered to my spouse.
Bottom line, build a list which meets your needs, looking for schools with similar values and priorities that you care about, across the rankings, and don’t get stuck looking only at T20.