GarageBand for iOS crashes at start on iPhone 7 Plus (iOS 15.7.7).

Hi Sir_Kermit-the-Frog,

Thanks for connecting with us here in Apple Support Communities. Rebooting and resetting GarageBand was a great to step to take. You may need to also delete the app and reinstall it as it may help to address the issue you're having. See: If an app on your iPhone or iPad stops responding, closes unexpectedly, or won’t open - Apple Support

If an app on your iPhone or iPad doesn't work as expected, try this.

Close and reopen the app

Force the app to close. Then open the app to see if it works as expected.

Restart your device

Restart your iPhone or restart your iPad. Then open the app to see if it works as expected.

Check for updates

To see if updates are available for the app, open the App Store, tap your profile icon, then scroll down to see if updates are available. If updates aren't available for the app, update the software on your iPhone or iPad.

Delete the app, then redownload it

Delete the app. When you do this, you might lose data that was stored in the app. Then redownload the app. Then check to see if the problem with the app is fixed.

Regards.

Hey there Sir_Kermit-the-Frog, 

At this point, you'll want to contact Apple Support for assistance.  

Have a good one!