Every since the new update network disconnecting and reconnecting constantly have tried replacement Sims and even gone to store. Update patch for that will greatly help
Clearing device cache via recovery mode can help resolve the vast majority of post-update issues.
Try resetting network settings as well.
If the issue persists and your carrier is unable to help, there may be a hardware issue at play. Visit a certified Samsung repair center to diagnose the issue and have any necessary repairs completed.
