While I agree that distance/interference can be issues with 5G, you’ve lost me with the speed of light comment.
The speed of light varies based on what it’s traveling through. The 186,200 miles/sec number is for a vacuum - it’s slower through anything else.
Here’s a good paper on remote surgery: https://arxiv.org/pdf/1803.03586.pdf It claims that 0.2 seconds has a “mild” impact. Note that that’s a round-trip delay. Remember, the surgeon does something, that something needs to happen, and then the video picture of what happened has to go back to the surgeon.
At any rate, robotic surgery won’t be the “hot” application that drives 5G.