This is almost certainly not really 5G. I will regularly get those speeds on my iPhone X with "5Ge", which is just three 4G download channels bonded and zero 5G infrastructure from the RAN toward the core. At your signal strength and your distance from Chicago, the latency on true 5G would be much less, like around 15ms and the throughput should be much higher. Unfortunately, 5G is technical spec and also a marketing term.
I don't know of any carrier that has their 5G backhaul network completed, much less designed.