Too right @GoForth! (re: “having difficulty” and “easing back the academic throttle while pushing forward the music throttle” are two different ideas). Music schools want to be sure you can handle the academic work, which is still very challenging at many schools. My son is a double major in performance and Music Ed at a conservatory and I think he has 19 or 20 credits this semester. But music schools do understand that the majority of HS musicians just cannot take 4-6 AP classes junior and senior year and have adequate time to practice and be on the top of their game musically. It is usually easier for a musician applying to a BM program to clear the academic bar than a general applicant at the same school. If your schedule is rigorous enough to show that you can balance some challenging classes and high level music, then you should be good almost anywhere. It also depends on the schools you’re targeting - if it’s a school like Northwestern, for example, or you are applying to double degree programs, you may need to keep the rigor higher than you would otherwise.
My son was a good student but not good enough to be considered for competitive academic merit awards. For him, it was a matter of easing up on APs, which are super time consuming at his school, and picking the slightly easier options. For example, honors senior English instead of AP Lit (he’d already had AP Lang), or regular physics instead of AP Physics in order to make sure he had the main 3 lab sciences. He actually started backing off junior year, when normally the good students at his school take 4-5 APs and he ultimately decided to take just one AP plus a few honors. He had a great junior year, managed stress well, and had some wonderful musical achievements he might not have had otherwise.
He still ended up with one too many AP class senior year, which became an issue when he had the demands of marching band plus prescreens/apps in the fall. He ended up dropping the most time consuming AP that had a lot of reading. I have been advising other music parents I know whose kids are academically talented but want to apply to BM programs to figure out the # of AP classes you are sure your kid can handle and then subtract one to account for the demands of applications, prescreens, auditions. Getting an A or even a B in a slightly less challenging class is going to look better for music admissions than a C in a difficult AP class.