They seem to follow projects, not presets. To my mind that seems correct since you can’t monitor what isn’t there, and what you monitor is the “mixer” which is recalled with each project.
I see what you’re saying. I’ve been using Monitor Sources with outputs exclusively, but now that you mention it, a Monitor Source attached to a Group that doesn’t exist might break the world.
Frankly, my understanding of settings stored in Preferences vs. Projects/Templates is lacking. And then there’s Profiles. Which settings get saved in what? Is there a list somewhere? An overarching logic?