I have some, but I don't know if they are accurate (otherwise I would have done the edit myself 😂). The existing relation is https://www.openstreetmap.org/relation/7317683 . Some people published a route (https://www.cirkwi.com/fr/circuit/428974-le-belarel) and I crossed the signs in Guirsch and where I placed this note (https://lab.kewl.lu/thumbsup/2023/media/original/02/24/20230224_170012.jpg; in this area it's an unpaved track but most of it is paved). There's also a  link on arlon.be which doesn't go there; so maybe the route changed? Might be worth a survey. 