iPhone 5s with iOS 12.0 not recognized by iTunes 12.8 on MacBook Pro Late 2011 High Sierra

Dear Community,

Since upgrading to iOS 12 on my iPhone 5s, iTunes does not detect the device when connected by USB. It was recognizing it just before the upgrade, when I was on iOS 11.4.1. With some cables I get the message "This accessory may not be supported." With others nothing happens, but with all of them the device does start charging. Checking in System Information, my iPhone appears within the USB section, so the computer is recognizing the device.

System information:

MacBook Pro 13-inch, Late 2011

macOS High Sierra version 10.13.6

iTunes 12.8.0.150

iPhone 5s 32GB iOS 12.0

Troubleshooting attempts:

- both USB ports with both Apple and other MFI-certified Lightning cables

- cleaning cables and phone charging port

- the suggestions on If your iOS 12 device isn't recognized by iTunes

- checking host files according to here

- removing all third-party security software according to here

- restarting programs and devices between each of these steps

iTunes still doesn't recognize my phone. The other computer (a PC) I normally connect to is currently unavailable so I have only been able to test this MacBook. Any other suggestions? Would restoring my phone from the backup I took just before updating to iOS 12 get me back to 11.4.1?

Thanks for your input,

Chris