Unable to update iOS. Stuck at verifying update. More than enough storage space and optimal internet. Celluar is also constantly searching for service. Results in battery being drained extremely fast. SIM card is inserted and placed correctly.

I noticed my phone was not working one day. IPhone 12 pro max constantly searching for cellular service. Results in battery draining and unable to make or receive phone calls or text. Cellular in settings says error. Device will not recognize any SIM put in there. There's no "NO SIM" in the Cellular bar area. No notification of "insert SIM". Thought it could be the iOS. Attempted to update iOS to 16.7.1 or iOS 17. But it is stuck at "verifying update". Have tried waiting for over 8 hours. Tried airplane mode on/off, reset network settings, recovery mode, lastly factory reset with erase all content and settings. Cellular issue still exists in factory setting and Can't activate the phone anymore. please help!