Hi elara256,
Are you able to see Minecraft listed in your past purchases? If so, what happens when you attempt to download it from there? The following guide explains how:
Redownload apps and games from Apple - Apple Support
If not, is it possible that a different Apple ID was used when the app was purchased?
If the app is shown in your past purchases, but will not download, it may also be the case that the Minecraft app in the App Store is a different app than the one originally purchased. For example, the developer may have released it to be a newer, enhanced or custom app.
If that's the case, and if the other Minecraft app is no longer available for download, it would be necessary to purchase this specific app. We can recommend reaching out to the developer directly to confirm.
Here's how to find contact information for any developer in the App Store:
How to contact an app developer - Apple Support
Take care!