I have the Luna USB-C adapter working from a Thunderbolt Dock.
I was existed if Luna would work with the dock, and the first try was a success.
As Apple gave the iMacs only two TB ports, I was looking for solution to get more of that Thunderbolt and USB-C “magic”.
I will not name the dock (send me a PM if you what to know which one it actually is), as I guess that any dock will work, that has a USB-C port with the DisplayPort logo together on a port.
If a port has that logo/trademark sign, then it is somehow certified.
I will attach a photo of the port and logos later.
All works like a charm. I tested the adapter and dock with an iMac 27’’ late 2017 and a MacBook Pro 2016 with TouchBar linking a second gen 10inch iPad Pro.
One cosmetic issue found, that is that in the “About this Mac” section for displays, the Luna Display does not appear. In all other parts of the system overview it is shown.
I have attached a photo (sorry German interface), but I guess you will get the point.
So long story short, if you buy a Thunderbolt dock and want to be sure that Luna Display attached to the dock will work is, that there is at least one USB-C port that has the DisplayPort logo on it. So USB-C logo and DisplayPort together.
Mine says in the description “1 USB-C™ DisplayPort™ Daten- und Stromanschluss (15 W)”.
Now I have three TB3 ports left. One is used by an external NVME and my iMac with Fusion Drive is now booting from that disk (1200 MB/s write and 2000 MB/s read, which makes the Fusion disk obsolete and I did not need to open the iMac and loose warranty to get this disk speed; PM me if wanna know more, about 440 bugs for 1TB; lots of money, but it is 1TB of M2 NVME storage).
P.S.: For testing purposes I had a full HD video running on the iPad Pro when I made the screen shots.