Try 'Network Reset' from phone settings. Search for the same under Settings (search icon) and it will point you to that setting. Then restart the phone. You will need to enter your Wi-Fi password again so make a note of that.
If still not working, I guess a Factory Reset should fix the issue. I suppose a major update was there in June (OS change from Android 10 to 11). A Factory Reset is anyways recommended for Android smartphones after OS change. Fixes most of the issues and makes the phone even smoother.
Use Samsung Smart Switch app for backup and restore. Take backup of contacts & messages as well. You may need to download the apps and games again, update the apps after Factory Reset.
Network reset you can try. No data loss. Or turn off phone and re-insert the SIM card properly. Also clean SIM card contacts and SIM tray with compressed air as dust accumulates over time.
I recommend to go for Factory Reset (after backup). This also fixes any other issues that might occur in the future since OS has changed.
For further assistance, register your concern in Samsung Members Application (Open Samsung Members Application > Get help > Send Feedback > Error report/Ask questions).
