Kingston doesn't seem to offer any support for Linux, so their new firmware is virtually non-existent to me. Why can't I just download the firmware and use standard nvme-cli tools to update the SSD, beats me. If Seagate (which by the way uses Phison E18 too) can do it, so can Kingston, Samsung, Crucial, Western Digital and many others.

Even better would be use Linux Vendor Firmware Service (https://fwupd.org/).