Which CalDigit dock? I have the TS3 Plus. Using its Ethernet port and Thunderbolt 3 to my laptop, I'm getting the expected 1,000 Mbps connection on my home network. Do you have a different model or maybe a defective unit?
After going through the same pains as the author of the piece, I switched to CalDigit as well. No concerns or problems for me on a Mac for about a year. I had one that went bad, but I bought it off Ebay so I figured that might be more my fault (and it might not even be bad, I think I set it up wrong with the wrong Thunderbolt cable (too long for the power needed).