Hello,
as you seem to have local knowledge: can you please add the allowed transport to the ferries, see https://wiki.openstreetmap.org/wiki/Tag:route=ferry

Additionally, the ferry end points/ ferry_terminal are not connected to the road network, which prevents routing. See the errors detected by Openstreetmap inspector routing view https://tools.geofabrik.de/osmi/?view=routing&lon=3.72509&lat=6.91597&zoom=10&baselayer=Geofabrik%20Standard&overlays=unconnected_open_ends_1