You can make and receive regular phone calls and text messages because the dialer and messaging apps are system apps.
Since you suspect a third-party app, follow these steps to remove recent or suspicious applications: How to Activate Safe Mode on SAMSUNG Galaxy A34...
How to Activate Safe Mode on SAMSUNG Galaxy A34 Safe Mode is a diagnostic tool on your Samsung Galaxy A34 that allows the system to run only with its original factory software and applications. By temporarily disabling third-party apps, you can identify if a specific download is causing crashes, battery drain, or freezing. Follow this guide to master Safe Mode on your device. Method 1: Using the Physical Buttons (When Powered On) You can make and receive regular phone calls
The screen is black, but the phone vibrates or lights up slightly. Solution: If the screen works in Safe Mode, you know the display isn't broken. The issue is an app that modified the display overlay permissions (like a blue light filter or chat head app). Follow this guide to master Safe Mode on your device
If the phone works perfectly: The issue is software-related (an app). If the phone still glitches: The issue is hardware or system firmware (you likely need a repair shop or a firmware reflash).
Sarah simply and tapped "Restart" . The phone rebooted, the "Safe mode" text disappeared, and all her regular apps (like Instagram and Spotify) came back online—working perfectly.