After waiting for review, making changes, then stuck "In Review", I made the major decision to pull my pro audio application from the App Store before it was even accepted. The friction generated from Apple's process is not worth what you are getting back. Consequently, the offering for audio in the Mac App Store itself look very amateur and are largely limited to toys. This is an uninspiring group to be associated with and given the delays, cost, and hamstringing due to sandboxing, the motivation to follow through is very low.
I would encourage Apple to rethink their macOS approach if they actually want developers to use this system. This has been an issue for many years, and the situation is not improved. I thought I'd try again this round, but have again given up on the wait and restrictions.