Your DICOM images have had the CSA headers removed. This means you lack details on the number of slices, slice timing and diffusion gradient direction. If you want to analyze your diffusion data, you will need to recover a set of your DICOMs before these crucial tags were stripped off.
https://nipy.org/nibabel/dicom/siemens_c...
This is a limitation of your images, not dcm2niix. Since your data comes from a Siemens instrument, you can work with your center's research collaboration manager.

I would always suggest updating to the latest stable release (v1.0.20220720): the DICOM and BIDS standards are evolving rapidly

https://github.com/rordenlab/dcm2niix/re...