I would open System Information (click the Apple menu, hold Option and it's the first item) and check in the Thunderbolt section if your XDR's "speed" is shown as 40Gb/s. If it's lower than 40Gb/s then check the cable from the Pro to the XDR.
After that I'd go to the USB section and find the XDR entry - the "Logi 4K Pro" should appear next to it on the same hub.
If it's not listed, I'd use a different cable (I think the camera comes with two?), a different port on the back of the XDR, etc. to try and eliminate possibilities. You could also try unplugging power from the XDR - maybe its USB hub needs a reset?