Thanks for helping me out!
Thanks for reaching out! Please note that the slightly longer route (by around 300m = 5%) is using designated cycle paths as well. When computing a route estimated travel time and the suitability of the ways are taken into account in an attempt to find the possibly optimal cycling route. Elevation changes and intersections are currently not being considered. For some reason in this particular example the longer route is seen as better by this heuristic.
Is it possible to grade the quality of the path somehow in OSM? Or are there some preferences in the routing algorithm that could be useful here?
There are many osm tags that are considered.
Please take a look at:
If you use a different cycling profile, default speeds might change depending on the specific flag encoder: