I open the ENC Direct data (any file) (https://www.charts.noaa.gov/ENCs/ENCs.shtml) in ArcMap using Esri's free S-57 loader extension and I'm able to see the SOUNDG_P layer and can display the Depth.
The data is definitely in there:
However, when I open the same file in QGIS, I see only points but no Z Value which are not in attributes.
Can you help me?