I'm curious - why doesn't UCX II have USB (3/thunderbolt) Type-C like UFX+ does? For a device released in 2021 that's kinda weird.
It should be known by now that RME only uses the I/O that is really necessary according to the bandwidth requirement in terms of number of channels.
Then customers have the advantage of being able to connect and use the recording interface on as many devices as possible (not every device has thunderbolt).
RME manages around 68 channels with USB2. So, why should they use Thunderbolt, which would only drive up the costs unnecessarily and raise unnecessary requirements to have thunderbolt in their computer.
Other manufacturers use thunderbolt because they didn't get it, managed to write capable drivers for USB or because they live in the Apple cloud of devices / connections.
BR Ramses - UFX III, 12Mic, XTC, ADI-2 Pro FS R BE, RayDAT, X10SRi-F, E5-1680v4, Win10Pro22H2, Cub13