A high school guidance counselor?
Black-box holistic admissions processes are nothing new, most selective institutions have overtly had them for decades even if they didn't tend to use the word “holistic” to describe them (they have weighted a wide range of factors beyond GPA and test scores, and have never announced how most of them were measured or how they, once individually measured, were aggregated, but advising on the that has been—since sometime I started preparing to apply to college in the late-1980s—a major function of high school counselors.
An expensive college consultant could tell you who and how to bribe to bypass the admissions process applicable to more plebian applicants, though.