FYI, my Pro Art 670E now works with the Pro XDR Display over TB4 -- without the need for a USB-C to DP+USB cable at 6k HDR with my Nvidia RTX4090 plugging into the DP-IN. I think Nvidia must have pushed an update in the last 6 months that fixed this behavior as ASUS pinpointed this worked previously with AMD cards. I also updated the BIOS to the latest, and I'm on the latest Win11 update -- so YMMV.
Note that the display also works with daisy chaining via the TS4 Dock, which was honestly pretty surprising.The only caveat is the USB is very flaky, and frequently I get an error the the USB hub on the back of the display isn't recognized. The display recognized by Apple's drivers, but that's fine since I can change the brightness with the Windows HDR settings, but I guess I can't change picture profiles either. Note that I also had to effectively move all my peripherals to the CalDigit TS4, which is fine given the plethora of inputs. But I was having weird resolution issues on my Mac (frequently only 4k) when forcing the pro XDR to use USB-C, so this is a huge quality of life improvement.