As an anecdote from Texas, i didn’t see good students with college consultants getting better acceptances then ones who did it on their own. Ones who had an edge were private school students and urban school students. Competitive suburban public school students were at disadvantage.
Neither did i see any difference for National Merit between students who did PSAT prep by themselves or ones who paid thousands to prep centers, good students made it regardless of if they had help or not and ones who wern’t at that level, couldn’t make it even after spending every free minute at prep centers from 7-12 grades.