5G coverage for me (UK, 3.6Ghz band) is actually much better than expected. Having tried 2 different networks (Three and Vodafone), Three's coverage map shows no 5G at my location, and Vodafone's shows the weakest band of signal. But in reality I actually get 5/5 5G signal strength and excellent, reliable download speeds on both, indoors. It probably helps that I'm on the 5th floor, but even on the street outside at ground level it's still 5/5.
This is with a Huawei mobile MiFi 5G router (E6878).
Vodafone seems to now have excellent 5G coverage throughout East London, pretty much wherever I go. Not quite so much in Central London yet, though, but it falls back seamlessly to 4G of course.