My 2015 PX Ford Ranger 4x4 dual-cab has a very loud injector noise under acceleration. I had similar issue with a 2008 Toyota Hilux 2008 that Toyota claimed was all clear, but when I took it to a diesel specialist I was told 3 out of 4 injectors were out. It was very expensive. Ford claims it cannot hear the noise, but it is as plain as day. It has only done 6000 km. What can you tell me?
From your description it does appear to be noisy injectors. Take it back to the dealership and have them assess the noise in your presence so you can make sure they are hearing what you hear. Once you've done that make a warranty claim to have it fixed.