@Brian-McG no problem, thanks for the answer anyway. I don't have any practical reason to don't use active navigation, I'm just used to use the passive one while riding. It's a kind of mixture between the paper map and the active navigation.

Attaching the track the road and then create a route or a new track in OsmAnd is possible. This is what I do for short tracks, about two or three days. Unfortunately it doesn't work for long tracks (sometimes it cuts the track in half or it doesn't find a solution at all).
The workaround I found is to split the route in segment of approx 1,500 km, export them to TomTom planner, recreate the route and export the GPX that has way more points than the MRA exporter.

@Corné-Voogt Do not use the Place waypoint button.
If you double tap the screen it will place a new route point in the correct order. This takes a little practice.