iPhone 7 plus camera 2x zoom doesn’t work, the portrait mode doesn’t work

There was no a software change to remove Portrait Mode.

From your description it seems like there's a problem with a second lens.

First, restart your iPhone. This basic step resolves a lot of issues. One day after update the Camera app just disappeared from my iPhone, lol. Then I would recommend to update to iOS 12.1.4. If this doesn't resolve your issue, try to restore your iPhone to factory settings. Don't forget to back your iPhone up. Set it up as new and check if an issue persists.

If it does, then schedule an appointment for diagnostics and repair.

I experience exactly the same behaviour. Pushing the 2x zoom button, and nothing happens. Portrait mode doesn't work. Nothing so far helped to solve it finally. Apple authorized service provider and Apple online support can't help me. They say it's a software malfunction, most likely caused by a third party app. But which one? Diagnosis discovers a problem with the camera, but no specification.

Sometimes a soft reset does the trick, then it works for 1 hour up to 2 weeks, but all of a sudden the problem comes back.

Reset and setup as a new iPhone works, but I can't setup the iPhone from scratch. When I restore from iCloud backup the problem comes back.

Any help is much appreciated.

iOS 12.1.4

iPhone 7 Plus

An encrypted backup requires a passcode, yes. But you can't recover it if you don't remember it. Note, that iTunes backup passcode is not the same passcode that you set for your iPhone. Try to remember what could you use.

Come back with the results.