I think the best course of action is to unlist and mute the banner topics, and indeed, use linked topics for staff.
Actually, I’m wondering whether the banner topics would work in a public, but muted category. That would solve all issues, since most of the time nobody wants to hear about the background work of community-related actions, but still might be interested – e.g., if they want to become an active host.
Yes! You can use a globally muted public category for banners.