PhotoLab 9 currently doesn’t support the new RX-10M5’s RAW files.
The work-around is to use exiftool to adjust the Model tag to M4, but this is only a work-around. While the lens is essentially the same as the M4, the image processing now goes through an updated processor. The mod gives PL9 access to decoded images, but they could be better.
exiftool.exe -Model=DSC-RX10M4 *.arw
The original files are kept; the extension is changed to arw_original.