It is offline - meaning you download the areas you are interested in first, after which all the data is available fully offline (including stuff like directions, metro maps etc). The interface takes a bit to get used to, but the biggest let down is the fact that you can't edit a route in the route planner - you need to start all over again (selecting start/destination, no way to modify either).
[0] - https://f-droid.org/en/packages/app.organicmaps/ (also available on Play Store)
As far as I know, it doesn't do pathfinding either. A client will have to take the data from OSM and use its own algorithms to navigate.
There is also a lot of clutter.
These are traits that have all gotten worse over the years. I'd prefer the UI of the first-gen Google Maps then what we have today.
I have no complaints about the actual navigation, there has been quirks over the years but nothing that stands out in my mind.
I have tried OpenStreetMaps (albeit 5+years ago) and couldn't search for an address. So if that's improved I'd like to know.
I don't need/want "find X near me" or fluff like "what restaurant's are open right now?".
All I want is navigation between current location and target address.