wonder if service should be able to use beach as option to create hiking route, or if should add path on it to be able to create such routes?
i think my answer from this post applies here as well
In case you defenitely want to go over the beach, you could also use the
skip_segments parameter, or like you proposed: create a footway there. But you should check if there are Guidlines or Restrictions from the OpenStreetMap community for this.