Honestly, you are going to want to use iTunes to restore the iPhone since the restore screen keeps popping up.
If you have a Mac, make sure that you've [link|https://support.apple.com/kb/HT201541|installed the latest software updates|new_window=true] (including iTunes if you have MacOS Mojave or earlier). Or on your Windows PC, make sure that you've [link|https://support.apple.com/kb/HT201352|installed the latest version of iTunes|new_window=true].
Now if you turn on your iPhone, and plug in the phone to the computer, with iTunes open, you'll see something that says: "There's a problem with the [your device name] that requires it to be updated or restored." Make sure you click on "Update" and wait for iTunes to finish.
If you're having trouble updating, take a look at this: [link|https://support.apple.com/en-us/HT204770|iOS update and restore errors|new_window=true]