I just connected my Horizon ¨Lidar, it was very noisy at first, later on I realized it must be the fan, but also made some extra noises, now it makes no more. The Lidar is new it just had been boxed for a long period. I watched the video and I was getting same noises as you, now only the fan noise.
I was not lucky to connecto to the livox viewer tho, seems discontinued can you tell me what version of livox viewer are you using?