The carriers often hide behind disclaimers that the map only shows outdoor coverage. It may be true that 5G is there, but you have to be above the tree line or out of the signal shadow created by say, a mountain or building. The maps are computer generated so, it's possible they didn't get generated with a lot of precision, or based on the actual engineering data.
It could also mean that Verizon has 5G ready equipment on the tower, but needed to turn it off due to a technical problem. For example, in my market, Verizon has a lot of towers with 5G surrounded by towers without 5G. I can tell by looking at the sites and using a tool called CellMapper, as well as Samsung Band Switcher to lock my phone to the 5G NR + 4G LTE Anchor band. Some towers are in need of new antennas/radios because they aren't using a newer "Remote Radio Unit" design all of the carriers (including Verizon) have switched to. Some towers are in need of backhaul upgrades, so I've heard from Verizon techs in the area. Some towers are just so old, they don't broadcast more than Band 13 and Band 66, and don't do LTE-A... and these towers in particular, are the ones causing trouble. You'll find many of these in rural areas, sometimes in urban and suburban areas.
A tower near me had 5G enabled for all of 5 days before Verizon shut it off, and that's likely because it sits a mile from a Microcell, and a "pre-historic" tower that last saw upgrades in 2012. Connecting to the Microcell and that "pre-historic" tower was a nightmare. You might have 5 bars of LTE, but speeds were less than 1Mbps in both directions. Or the phone would stay locked onto 5G and you'd be left with a 1 bar barely usable signal anyways. When 5G was turned off, all of a sudden network performance went back up - 20Mbps on the "Pre-historic" tower and 50Mbps on the Microcell. Where towers have been upgraded, it's smooth as butter going between multiple towers, data speeds are high (100+Mbps) and I don't see strange problems.
The 5G NR network is less than a year old, so it's likely needing time to get up to meeting the coverage map in performance. Between the silicon shortages, the lack of infrastructure upgrades across the country on ALL providers until recent, and the fact that there is high demand on labor for Fiber and Wireless installers and engineers, it's taking time. But I do agree - understate rather than overstate. It sets a better expectation and the negative press about lacking coverage is better than negative press about 5G not existing where it should be.
