Sounds like an environment issue. Is bidskit installed in a certain environment, like with conda? If so, you can update dcm2niix in that environment (probably with pip as well). I am guessing that whatever is in your environment is superceeding the one you are installing with sudo.
Alternatively, maybe dcm2niix is installed in the Docker container Docker
You can always find the latest stable release of dcm2niix here, currently v1.0.20230411. Note that Debian systems tend to freeze software at the time of release. The BIDS, DICOM and manufacturers interpretation of DICOM are all evolving rapidly, so I would make sure you ensure you have the latest stable release (in particular if you have a Siemens scanner that was upgraded to XA).