I don’t know why; I’m designing a new announcement page. While there are currently six collection pages, only one collection page option appears when I try to link (binding).
Linking to a collection page using the purple collection link feature requires a collection item as context. You’ll see that option when you are configuring a link that’s inside of a collection list, or on a collection page - and it will always relate to the collection & item you’re viewing.
If you want to link directly to a collection page in another collection, you can do that using a literal link, like-