This is a pure unoptimized C interpreter right now; it needs to be made to e.g. not kernel panic booting miniroot before anyone can even think of making it go fast. That is why the sound breaks up and the events drop. If you can manage to press F11 without macOS intercepting it you'll see just how poorly everything is actually running.
What format are your CD images in that CHDMAN isn't working? ISO is standard for workstation software, as it typically doesn't have audio tracks.
