Plugin decodebin should be able to manage various encodings, but I cannot reliabily use it with nvv4l2h264 encoded stream.
gst-launch-1.0 -ev rtspsrc location=rtsp://127.0.0.1:8554/test ! decodebin ! nvvidconv ! xvimagesink
If you want to be sure using HW decoder, on Jetson you may try this for reading H264 encoded stream and display:
gst-launch-1.0 -ev rtspsrc location=rtsp://127.0.0.1:8554/test ! rtph264depay ! h264parse ! omxh264dec ! nvvidconv ! xvimagesink
For H265 you would just replace replace h264 with h265.