Here’s a pic showing a Mokin dongle and its internals: From Mokin’s site. They may manufacture the cases and simpler electronics, but they purchase lot (or all of) the fancier tech from manufacturers, such as networking chips.
I had a pretty good guess why this was happening and how to fix it. The dongle worked like a charm out of the box with the notable exception of one part: The Ethernet port. I recently got a Mokin 10-in-1 USB-C dongle for use with my work computer, a 2019 16″ MacBook Pro, whose only connectors are 4 Thunderbolt/USB-C ports and a 3.5 mm audio jack.