Earlier quoted context omitted.
I think mapy [1] is the best frontend I've seen for OSM. Its search still isn't as good as Google Maps though. They also have iOS [2] and Android [3] apps. I can't speak for the iOS app, but the Android one lets you download offline maps in a very space efficient way, similar to Organic Maps. 1. https://en.mapy.cz/zakladni?x=-2.2989613&y=53.1629710&z=8 2. https://apps.apple.com/cz/app/mapy-cz-maps-navigation/id4114..…
I feel like an ass just for saying it but I downloaded the iOS app at the map style is so… busy. Granted I’m in NYC so there’s a lot going on but it’s showing me every single bus stop (there are literally seven in a one block radius) and building outlines even when zoomed out. It’s very visually overwhelming. This is something Google and Apple Maps really nail, I hope OSM can too at some point.
So if I could respectfully amend your request, I'd say I hope some third party can really nail this at some point. Organic Maps is pretty good, but I still need Google maps for a number of things. But even if that doesn't ever happen, the free OSM data is invaluable in a large number of GIS contexts.
(I'm an opinionated OSM contributor since 2007. :)