Unable to answer "What’s the surface firmness of this track?" – Track / Land-Access Road – https://osm.org/way/708194296 via StreetComplete 57.3:

Mauvais attribut. C'est un sentier de promenade. Aucun véhicule motoriséne passe.

Attached photo(s):
https://westnordost.de/p/215094.jpg