After an investigation, the Justice Dept concluded in Jan 2021 that likely there was a collusion amongst the DC area private schools to eliminate AP courses from their curriculum. However, DOJ decided not to bring enforcement action after the schools affirmed that they "have not and will not be colluding" regarding the elimination of AP courses.
https://www.justice.gov/archives/opa/pr/justice-department-concludes-its-investigation-dc-area-private-high-schools-decision-stop
Understand that private schools stop offering AP courses for differentiation purposes. Why would parents pay tuition up to $70K per year if their kids can get the same AP courses at their high-performing local public school for free?
OP need not be concerned about selective college admission rate without taking AP. It has stayed practically the same. Yes, there are students who take AP exams on their own and do well, because they want to earned advanced credit in college (good idea) and/or skip introductory college classes (bad idea). A few years ago, a science teacher in the #1 private school in DC told me that they are supportive of students who want to take AP exams.