Is there a recommendation for OSM on mobile? IIRC they don't have an official app.
Also looking at their bike routing - it gives me an idea. Road should be rated on whether they have a dedicated bike lane and on the danger of riding on said road at particular times of day. I just input a src/dest and it gave me a really busy road with tons of "paperboy" level risky side roads on it. I would never want someone to take that route at 5pm on a weekday.
OSM is fundamentally just a DB for place locations and geometries. Directions use routing engines which choose roads and paths between locations based on constraints. The main landing page for OSM lets you choose between OSM, Grasshopper, and the Valhalla routing engines.
To figure out why directions are bad you need to see which criteria the routing engine is using to create the route and decide either to change the constraints used to generate the bike route or what added data you need to place on the streets for the routing engine to avoid/prefer certain streets.
Does this sound like an opaque nightmare? Yes. That's why very few people use it. Apple has been doing some great work doing mapping and adding it into the OSM DB, which they use for their own maps, but they have their own proprietary routing system for directions. If you're looking for a good app to use just OSM data, I use OSMAnd for Android. I still prefer Google Maps because their routing and geocoding tend to be much better for urban areas but for hikes and country bike rides, OSM tends to outperform GMaps.
Also looking at their bike routing - it gives me an idea. Road should be rated on whether they have a dedicated bike lane and on the danger of riding on said road at particular times of day. I just input a src/dest and it gave me a really busy road with tons of "paperboy" level risky side roads on it. I would never want someone to take that route at 5pm on a weekday.