disappearing apps

It may be hidden. For information about hidden pages, see the following from Organize the Home Screen and App Library on your iPhone - Apple Support

Find, hide, and remove pages on your Home Screen

With iOS 14 and later, you can hide pages to streamline how your Home Screen looks and add them back whenever you want. Here's how to hide a page:

1. Touch and hold an empty area on your Home Screen.
2. Tap the dots near the bottom of your screen.
3. Tap the circle under the page that you want to hide.
4. Tap Done. 

To unhide a page, repeat the steps above. Then use the App Library to quickly find apps hidden on different pages.

To remove pages from your Home Screen:

1. Touch and hold an empty area on your Home Screen.
2. Tap the dots near the bottom of your screen.
3. Tap the circle under the page that you want to hide.
4. Tap the Remove button (minus sign), then tap Remove. 

When you remove a page from your Home Screen, the apps will still appear in the App Library.

Thank you, very helpful!