People are losing the point of the initial post. It’s not whether dual enrollment or AP is worthwhile. In most cases dual enrollment/IB/AP is very worthwhile. It’s whether taking a course at a high school taught by a high school teacher that then gets an accompanying “letter grade” from a university is worthwhile at a cost of $325/course.
Will colleges accept this? And what is the point in taking “college-level” algebra2/trig when that’s a level of math colleges expect students to have mastered in high school? It’s not going to get a student any credits at most reputable colleges.