Hi there bj49wd,
Instead of trying to download the app directly in the App Store, you'll want to be sure you're viewing the App Store account and selecting the family member who originally purchased the app, then attempt to download it from there. Follow these steps to do so:
1. Open the App Store app.
2. Tap the sign-in button
or your photo at the top of the screen.
3. Tap Purchased.
4. If you use Family Sharing, tap My Purchases or choose a family member’s name to see content that they purchased.
5. Tap "Not on this [device]."
6. Find the app that you want to download, then tap the download button
.
You'll find those steps here: Redownload apps and games from Apple - Apple Support
If you still can't find the app or download it with those steps, you'll want to reach out to Apple Support directly for further assistance. They're best-equipped to take a closer look and provide some additional guidance. This link will help you get started: Contact - Official Apple Support
Take care.