When 5G first rolled out this was absolutely not the case. Not only was it not 1ms, it was like full 1000's of ms to the point where I actively turned off 5G on my iPhone because it was so bad.

I can only speculate 5G was so saturated on the initial rollout so it led to congestion and now its stabilized. But latency isn't only affected by distance and hops - congestion matters.