Is there a way to search for the "amenity:drinking_water" tag directly in OSMand or CoMaps (or any other app)? Because this would probably fix everything.
In the end, the apps suffer from the complexity of the underlying data. It probably wasn't a good idea to have drinking water (tourism), drinking water (store) and drinking water (man made), fountain, water tab, well, ... and probably a dozen different categories for map makers to chose from.