It’s well known that the “Open app” action accepts app names as text variables. However, there’s a variety of native iOS apps that their names are not recognized by the mentioned action (eg: Messages, Safari, Settings etc).

To overcome this restriction just use the app’s bundle identifier name instead! This is a simple dictionary shortcutthat includes all bundle ids for native iOS apps

Open app bundleID vs Text 

BundleID for Apple Apps is likely the better way to go in many cases, but third party app name shouldn’t have an issue. My Focused Apps shortcuts uses app names but sometimes runs into issues with Apples apps. I haven’t updated it to use bundle ID’S just yet. Just in case it’s needed, there’s also a post on how to get the BundleID of any app.

r/shortcuts - Passing a text variable to an “Open App” action

Focused Apps - A single Dynamic App Launcher that displays a different list of selected apps to launch based on the currently active Focus Mode. : r/shortcuts

r/shortcuts - Find Bundle ID of any app