I think the fundamental issue here is that students (and their parents) get into this mindset while applying for undergraduate programs that they have to just check a bunch of neat little boxes to increase their chances of admissions. Graduate admissions, and especial doctoral admissions, are much more holistic than that.
You can’t get by just by checking a box for research. Ultimately, what matters more than research experience is the quality of that experience, particularly as attested to in one or more of an applicant’s reference letters. If I am admitting a PhD student, what I want to determine is whether they have both the academic chops to handle the coursework as well as the desire and ability to perform as an independent researcher. “AP Research” tells me none of that, nor does a generic research experience. If, on the other hand, a letter from a faculty PI tells me that said student was great in their lab and has a lot of potential, that is just about the strongest endorsement I can find for a candidate.