What does ⌛︎ Preview Hidden in macOS Messages app mean?
I had this too and this seemed to give me what I wanted (the preview): System Preferences->Notifications->Messages->Show Notification Preview->set to Always. Then Quit Messages and restart.
I had this too and this seemed to give me what I wanted (the preview): System Preferences->Notifications->Messages->Show Notification Preview->set to Always. Then Quit Messages and restart.