Hi,
This is design of Xavier NX module. Please refer to the topics:
connected more than two usb cameras problem on deepstream-app (Jetson Nano Dev Kit) - #12 by DaneLLL
DeepStream4 Jetson nano multiple webcams issue - #12 by DaneLLL
On Xavier, there are one type-A port and two type-C ports. If you have multiple D435i, we would suggest connect each port with single camera. For connecting to type-C port you would need type-C to A adapter. The realsense cameras require significant bandwidth and it is better to connect each one to single USB3 root hub.