@Con-Hennekens I think this was also possible with the Garmin Zumos, from what I remember the route path was made up of different segments,
the path you had already traversed, the immediate next segment & then future segments, you could edit the colours of each segment by hacking the html,
I mainly used it for adjusting the widths of the path segments so I could also see the edges of the track poking out the sides of the route path, similar to the white line in mRA