iPhone X no service issue.

My iPhone X frequently shows NO SERVICE, even though I am in a good network zone the network vanishes. I did notify my network provider, however as per their technical team they reset the network settings, also did other possible network troubleshooting like restarting the phone, turning the phone off and on, removing the sim and turning the airplane mode off and on, but the issue still remains the same. The network team did also visit my work and home location to identify if the issue was with the network however it showed up to be a good network zone. I even swapped the sim with another network provider and its the same. In regards to this I also checked with my fellow colleagues and friends who are using the same model or different model with the same brand, a few are facing the same issue like I am while for a few it has just happened once and never again. Could you please let me know if this issue is due to the iOS and will there be fix for this issue soon ?