• VLC in ubuntu 20.04 supports RTSP but does not in 22.04
• snap VLC in 22.04 supports RTSP
• easiest might be ffplay:

ffplay rtsp://<IP ADDR>/profile2/media.smp

• send to loopback /dev/video0:

ffmpeg -i rtsp://<IP ADDR>/profile2/media.smp -f v4l2 -vf format=yuv420p -loglevel error /dev/video0