New SanDisk Plus NVMe and Beikell USB-C enclosure not SMART enabled?

Not all USB drives have access to SMART data as it requires some extended protocols to supported by the enclosure hardware (SCSI ATA Translation or SAT for short) plus macOS does not support SMART over USB without special third party drivers.

The NVMe itself alone will likely support SMART (I don't know of any "raw" mass storage device that doesn't, SSD or HDD).

The issue can be the USB enclosure and macOS itself not supporting SMART over USB without a third party driver and an app that interfaces to it.

If this is a USB enclosure, then you need to install a special USB driver to attempt to access the SMART health information on the external USB drive. You can get the special USB driver from the DriveDx website....they have great instructions for uninstalling the driver as well.

https://binaryfruit.com/drivedx/usb-drive-support

FYI, even with a great app like DriveDx, you still need to manually interpret the SSD's SMART health information since any Warning or Failing notices may not necessarily mean the SSD is bad. Unfortunately most NVMe based SSDs have very little SMART health attributes to monitor so interpreting an SSD's health is not easy. At best if you see the number of Bytes written reach excessive values or it mentions some errors, but are they really serious? Hard to say.

Whenever I suspect the SSD is the problem and the SSD is reporting some SMART errors, then I will use Linux to access the SSD's built-in hardware Secure Erase feature to reset the SSD to factory defaults which many times will fix the SSD's problems.

Most SSDs fail without any warning due to issues with the SSD's controller. At best you may get a warning where the SSD goes missing when you first power on the SSD or when waking the SSD from sleep.

Also, the "SMART status" condition in Disk Utility is like Pass/Fail. For Hard Drives I only ever saw Disk Utility report "SMART status failed" two times....usually Hard Drives are unusable long before the SMART failed status is triggered.....the SMART attributes if they were monitored would have provided a much earlier warning of a problem before the user would even notice a problem. With an SSD it is more likely to see a "SMART Status Failed", but the SSD may continue working for years more. I have multiple SSDs where one of the SMART attributes has triggered a "Failed" state, but that is only part of the story of the SSD's health.