What if the speed of light was 2c instead of c? Would that change anything for us?

Less latency in multiplayer games or Zoom calls. Because light can travel around the Earth 7 times in one second, that means one roundtrip to a server on the other side of the world must take ~140 ms (1/7th of a second) which is a timescale you are able to feel. That's lag in multiplayer games. I'm constantly amazed that the reason why multiplayer client-side prediction strategies like rollback netcode exist is because light is slow enough on a human scale that we actually have to architect around it. Light is surprisingly slow in some ways.

The universe would look very different probably.