PROBLEM SOLVED!(The short answer is that the data transfer rate of my new type C to type C cable was only USB 2.0, something not specifically mentioned in the ad).
The longer story (FWIW):
I went ahead and updated the chipset and bios as suggested. In fact, I don't remember how far behind my chipset version was but my bios was at least 4 versions late.
Well, when I tried the type C connector is in the I/O panel port after the updates, the speed of the externally connected NVMe SSD was just a slow as before. In fact, this prompted me to investigate if my type C to type C cable has something to do with it.
Of course it did! The brand-new type C to type C cable that I bought advertised a "100W" connection but I didn't know that had nothing to do with data transfer.
Upon researching this cable and others, I found that the type C cables are manufactured without any kind of color code or inscription to indicate their data transfer rate. When they went from USB 2.0 to USB 3.0, they color-coded the 3.0 with a "blue tongue".
I thought that was a great idea and I really wish they would continue to do that or at the very least, inscribe the cable with its specified data transfer rate. I wish the manufacturers of these cables would have continued to use a color-code or labeling system for cables like; HDMI, DPI, numerous variations of USB to type C and mini USB 2.0/3.0/3.1 connectors.
Anyway, the point is that the NVMe enclosure I purchased was designed for the fastest speeds of such a drive. I also made sure it couldn't accept anything but an SSD type drive as opposed to those that can accept SSD and SATA drives.
However, this enclosure came with a 6 inch long type C to type C cable. Obviously, it was meant for someone with a laptop and that's why I purchased a 10 foot long type C to type C cable. Unfortunately, it was of the USB 2.0 data transfer rate gender. It didn't specify that in the had, which I'm to understand would automatically mean it is USB 2.0, (...I suppose...).
So, I purchased a 10 foot long, type C to type C, USB 3.1, GEN2 cable, which arrived tonight. I connected it to my type C port in the I/O panel, and got very fast speeds from the externally enclosed NVMe SSD.