I moved a formatted NVMe from one USB adapter to another USB adaptor and rebooted the host. ESXi GUI saw it as USB accessible storage, but would not mount it as a DATASTORE. Let's fix that!
# esxcli storage vmfs snapshot list
612fd952-87ba1925-3294-e45f012e79af
Volume Name: CYBERPUNK_NVMe
VMFS UUID: 612fd952-87ba1925-3294-e45f012e79af <-- note
Can mount: true
Reason for un-mountability:
Can resignature: true
Reason for non-resignaturability:
Unresolved Extent Count: 1
esxcli storage vmfs snapshot mount -u 612fd952-87ba1925-3294-e45f012e79af
# df -h
Filesystem Size Used Available Use% Mounted on
NFS 529.4G 438.9G 90.5G 83% /vmfs/volumes/SANDATASTORE
VMFS-6 931.2G 89.4G 841.9G 10% /vmfs/volumes/CYBERPUNK_NVMe
VFFS 13.8G 2.6G 11.1G 19% /vmfs/volumes/OSDATA-613a47c6-0701eb8e-8416-e45f012e79af
vfat 1023.8M 116.7M 907.2M 11% /vmfs/volumes/BOOTBANK1
vfat 1023.8M 32.0K 1023.8M 0% /vmfs/volumes/BOOTBANK2
Now GUI has auto-mounted as usable DATASTORE!