Due to shorter wavelength, 5G will have worse coverage in terms of distance from the station. So in rural areas you will not see improvements unless density of stations is increased.
However you can fit a lot more in terms of nodes and bandwidth compared to 4G, so in congested areas like cities you may perceive better "coverage" as a result.
> 5G compared to 4G since the former needs more sparsely distributed nodes
...It’s the opposite, no? But yes, my understanding is that area coverage would not improve simply by upgrading/switching out existing stations. You would need a larger number of stations/energy to cover the same area with 5G vs 4G.
High band 5G (the exciting, fast mm-wave stuff) certainly can improve service in a highly congested area, like a stadium, but low and mid-band offered in combination with legacy 4G will improve service most places in the world.
Some of the new spectrum is lower frequency, in the US former TV channels 52-69 (700Mhz) were reallocated around 2008 and mostly used for LTE, former TV channels 38-51 (600Mhz) were reallocated around 2020 and will be mostly used for 5G. This new UHF spectrum may propigate further and help close some gaps in coverage.