A bottom sheet, drawer, etc. (lots of names, I'll be calling it sheet) is used a lot in apps and there are a lot of RN packages for it. I need one top-down, not bottom-up. The video below shows what I need, but top-down instead of bottom-up.
The image below is a screenshot of the app. The red bar at the top needs to be pulled down to open a second window (this may be a modal). The sheet must be over the tab navigator at the bottom (Home, Subjects, etc.), and must be able to navigate to another page and back. This bar currently sits on a custom header that's loaded via React Navigation's header object. This header receives the navigation prop from the page it's loaded in from. It's no issue if it basically extends the total height of the header to the full page (this will probably the easiest solution). Must work on both android and iOS. We're using expo.
I noticed this package has a height offset which may be quite useful.
EDIT: We're currently testing react-native-slide-down. We'll update the post when we have any results on it.