If you are from (or studied in) North America, you will not need the following, but some students from Europe, India (and perhaps other parts of the world) will find it useful (please feel free to add your views in the comments).

North American universities require recommendation letters from candidates. Why? And, given that all letters will be unanimously positive, what is their purpose?

First of all, the basis, as explained in this post (https://elisafreschi.com/2024/03/02/recommendation-letters-dos-and-dents/), North American universities (at least as far as I know), expect letters coming from people who know you well, not from “superstars” whom you met once at a conference. The latter are useless and I will not discuss them here. The former, by contrast, are useful, (but only) insofar as they can give the committee additional information that could not be derived from the transcripts, writing sample etc. This means that a letter should address aspects of your personality that cannot be present in the transcript. For instance, a letter can explain why you took longer than expected in your BA (e.g., because you were seriously ill), or why you had a bad first term and how you completely changed now. On top of that, a letter can explain your personality traits and how they mean that you are a great student (you are collegial, a team-player etc.), and will make a great colleague. Ask your letter-writer to be very specific (tell about that time when you were brilliant in class, about that time when your paper ended up sparking a unique discussion etc.).
In sum, the letter should complement your application, not just repeat what is written elsewhere (although it can repeat some of the key elements of your letter and transcripts), it should *not* be a generic statement of praise.