iPhone 12 pro max “No Service” issue

I received a new iPhone 12 Pro Max as a replacement under AppleCare+ in October 2023

The problem I'm having is that I randomly lose signal show “No Service” all the time, about 4-5 times a day

I solved the problem by 

• Reset network 
• Reset all settings 
• Contacted with Mobile Operator
• Factory reset on mobile 
• Factory reset by iTunes 
• Bring it to Apple Store at Central World (Thailand)
• Contact with Apple support 

Until now “The problem has not been resolved yet“

Has anyone else experienced this problem? And how did you solve it?