I cannot update my iPhone 7 while connected to my iMac. I do NOT want to hit restore. Phone is unresponsive, even power cable doesn't seem to register as connected.

Connect iPhone to Mac

Use your USB lightening cable --> Resolve USB-related alerts in iTunes - Apple Support

If unable to connect --> If iTunes doesn't recognize your iPhone, iPad, or iPod - Apple Support

For your Mac --> If your computer doesn't recognize your iPhone, iPad, or iPod ...

Use genuine cable --> Identify counterfeit or uncertified Lightning connector accessories ...

See how to --> Sync your iPhone, iPad, or iPod using iTunes on your computer ...

If you are experiencing an issue not listed here, contact support

I suffered a catastrophic failure, caused by internal device malfunction. Eventually found this: I found my problem: my iphone had a catastrophic failure because it was manufactured in China. https://support.apple.com/ja-jp/iphone-7-no-service

certain iPhones made in China had a problem: my serial number matched. “Bring to Apple Store for replacement”. I went immediately because I cannot work without my phone. They took it, restored to factory-settings: “here: fixed!”... lost all my data and same crappy device. Happen again?

I’m so mad right now. Apple just continues to disappoint.