This "ghost notification" issue, where your badge count shows unread texts, but the conversation list appears empty or stale, is typically caused by a database indexing glitch or an accidental filter view.
The most effective fix is to activate Siri and specifically say, "Read my unread messages," which forces the system to locate and process the "stuck" texts, often causing them to immediately reappear in your list.
If that doesn't work, check the top-left corner of the Messages app; if you see a "Filters" button, tap it and select "All Messages" to ensure you aren't accidentally hiding texts from unknown numbers.
Finally, if the list remains frozen, you can try forcing a UI refresh by tapping Edit (or the three dots) > Select Messages and then Read All (if available) or reset the connection entirely by toggling "Use on this iPhone" off and back on in Settings > [Your Name] > iCloud > Messages.