Thank you for the suggestion. I have already tried flashing with the latest official BSP (R36.3.0) and the issue persists.
The flash process starts but fails when attempting to write to the external NVMe, giving the same error indicating the device is unavailable, even though it is correctly installed.
Here are the details of my attempt with the latest BSP:
Debug: error: External storage device (/dev/nvme0n1) might be unavailable or not work correctly. Please unplug the power supply and reattach the external storage.
Error: Flash failure
The latest official BSP is r36.5 (JetPack 6.2.2). JetPack Archive | NVIDIA Developer
Please try that version and add the --erase-all argument to the flashing commands.