I recently saw one child into college, and have another on the way. I've spoken to many admissions officers, counselors, and similar folks making admissions choices for public and private universities.
To a one, they all claim to be looking for two things: (1) students who will succeed at their university, and (2) a diverse range of students to avoid a monoculture.
This means they try to look at the "whole student." For some students, that means academics and test scores to show academic prowess. For others, it's working summers to pay for their college to show it's a personally meaningful step for them. For others, it's being a primary caregiver to siblings or parents while still meeting college requirements to show grit and determination. For others, it's demonstrating consistent progress in pursuing a passion (e.g., volunteering or music or art) with a trajectory that continues through college.
Admission officers say they want a student body comprised of all of the above, and that's how they get the diverse range of students to create a dynamic learning environment.
Some of the least interesting students are "box checkers" who have a bunch of disconnected extra-curriculars that don't show passion, direction, or a proclivity towards success. If a student defines "success" as "getting into college," then what will they do once they get there? Probably flounder.
Test scores can be a useful data point towards determining collegiate success, but it certainly won't be the only one used. Nor will extra-curriculars or any other single factor.
The single biggest piece of advice for any applying student: create a narrative that shows how your activities (whatever they are) demonstrate why you will be a successful student that achieves your major-related goals. Your grades, scores, work life, home life, interests, and personal experiences should all be connected to show you are thoughtful, motivated, driven, and have your shit together. Do that, and you'll have the best chance of success at most admissions offices.