Towpaths are considered service roads, not cycleways. See https://wiki.openstreetmap.org/wiki/NL:Jaagpad
You have re-opened access to this segment: https://www.openstreetmap.org/way/1305379025 for bicycles and pedestrians, but as far as I know the path will remain closed for more than a year because of the works at the Bospoort brug. Has the situation changed already?