I am getting "Cellular Issue Detected" error on my iPhone 12

RenegadeRider wrote:

My iPhone 12, which is 3 years old, suddenly started showing a "Cellular Issue Detected" error, and it constantly searches for a network. At first, I thought it was a SIM card problem, but after testing the SIM in another Android phone, I realized it's a mobile issue.

I took it to a technician at iPlanet, and they diagnosed it as a hardware issue, saying the entire board needs to be replaced. My current iOS version is 17.5.1, and there's an update available (17.6.1), but when I try to update, the screen freezes at "Verifying Update."

I’ve already tried resetting the network settings and performing a hard reboot, but nothing has worked. The technician also mentioned that attempting a full reset or restore could potentially render the phone completely unusable—basically turning it into a "brick." At least for now, I can still use it like an iPad with WiFi

Has anyone else faced this issue, and is there a way to resolve it?

[Re-Titled by Moderator]

Put your iPhone in diagnostics mode - identify potential hardware and software issues

How to put your iPhone in diagnostics mode - Apple Support

you can try DFU mode

If your iPhone won't turn on or is black /frozen / stuck

If your iPhone won't turn on or is frozen - Apple Support

If you can't update or restore your iPhone or iPod touch Recovery mode

If you can't update or restore your iPhone or iPod touch - Apple Support

see https://imazing.com/guides/how-to-put-iphone-ipad-into-recovery-or-dfu-mode

If your iPhone won't update - Trouble shooting

If your iPhone or iPad won't update - Apple Support

iPhone Repair and Service - Apple Support

iPhone Repair & Service - Apple Support

Apple Authorized Service Providers and Independent Repair Providers

Repair Provider Verification - Official Apple Support

Check Device Coverage

Check Your Service and Support Coverage - Apple Support