P: Fujifilm HDR RAF support

It would be great to be able to do regular HDR merge of Fuji HDR Raf files. Currently, the HDR Merge option is grayed out.

The article https://helpx.adobe.com/camera-raw/using/fujifilm-hdr-raf-support.html says such HDR RAF files have to be converted to DNG.

First of all, I don't even see such option in Lightroom CC (non-Classic), I am using Lightroom 6.4.

Second, according to article https://petapixel.com/2021/02/15/understanding-fujifilm-high-dynamic-range/ even after merge the DNG still does not contain those over and underexposed images.