VLC can't play video stream from Orin AGX

SDP file is required for dynamic payload. You may use RTP/MP2T that uses a static payload (33) and can be used with H264 or H265.
Try as sender:

out_pipeline_str << "appsrc ! video/x-raw, format=(string)BGR ! "
"videoconvert ! video/x-raw, format=(string)BGRx ! nvvidconv ! "
"video/x-raw(memory:NVMM), format=(string)NV12 ! nvv4l2h264enc insert-sps-pps=true insert-vui=true idrinterval=15 ! "
"h264parse ! mpegtsmux ! rtpmp2tpay ! udpsink host=HOST_IP port=8001 auto-multicast=0";

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