Hey there coralbeach,
Thanks for reaching out to the Apple Support Communities. So we understand the issue correctly, are you having issues with apps being offloaded unexpectedly, or are you unable to redownload offloaded apps from the App Store?
If having issues with redownloading apps, check out the steps listed in the following resource that can help: If there's an issue when you redownload apps, movies, or other content from Apple - Apple Support
If you're seeing that apps are needing to be redownloaded after transferring data from a previous iPhone to a new device, this would be expected behavior if you restored a previous backup or used Quick Start to transfer your data. After your iPhone has been set up, your purchased apps should automatically download again from the App Store.
Let us know if that's able to help.
Have a great day!