Meanwhile - maybe after an update - it takes me back to the route. If I drive a different way than indicated, it wants to go back to the place where I left the route: "Please turn around". Later, it shows a route that leads back to the indicated route. If I then follow his route again: "Route found".

There is a function "Take the shortest route to the starting point", or "Return the same way to the starting point". Once when a diversion was signalled and I subsequently turned back onto the route, the device had trouble finding its way again for a while. I am not aware of a function "Back on the way" or even on the shortest route. Maybe I haven't found it yet or never needed it.