There have been reports in the past of PureRAW producing black image files.
I appear to have solved this on my new PC.
I have just purchased an Acer Nitro 5 with a RTX 3060 GPU and i9 CPU. The software would convert the first RAW image but all subsequent RAWs produced a black image (JPG or DNG). I noticed two things - the JPG file size was small and therefore incomplete - that PureRAW uses a separate executable called “DxO PureRAW 2 - File Saving”, presumably to do the file saving! Realising that the file saver may be where the problem lay I went into Setup > System > Display > Graphics and added this program to the list of those which could be set to use or not use the GPU. I set it to always run using “Power Saving” mode so that it only uses the Intel graphics, leaving the main program free to use the fast GPU. I also set "Don’t use optimisations for windowed games. The problem was cured.
I tested the fix using a mix of RW2 (Panasonic) and ORP (Olympus) files, all off 20MP cameras, with lenses ranging from 9mm to 400mm. Despite leaving the network busy downloading OneDrive files in the background, I processed 660 RAW files at a rate of 1 every 9.3 seconds. I then set PureRaw to run exclusively with the RTX 3060, and isolated the PC from the internet, achieving a marginal speed increase (a sample of 100 files @ 8.4 seconds each).
I have seen a workaround to the black files problem that suggested running PureRaw itself in Power Saving but that slowed progress to less than 1 image per minute.
I can’t promise this solution will work on other PCs but it is worth a try!