Neither. The CSV-1460 uses DisplayLink (software and USB) to do video.
You can connect it to a Type-A port and get the same result.
I am unfamiliar with the DisplayLink software or how it interacts with the GPU. I suppose it’s possible to have a GPU render to a RAM buffer and have DisplayLink output that? GPUs are faster when rendering to their own VRAM. DisplayLink also has to compress the info (12 Gbps for 4K 60Hz 8bpc RGB) down to USB 3.0 speed (5 Gbps).
Maybe you can go to the https://www.displaylink.com website to find answers.
A real display connected to a real GPU should appear in the Device Manager (view by connection) as a display device with the GPU device as the display’s parent.