It would be the 2019 route in reverse. The fast, flat road from Slovenia that goes through Croatia and in to Serbia via Vradzhin, Osiek, etc.
Not sure exactly where you would have to turn right to get back to Albania, but my default would be to use as much of that road as made sense, rather than the more direct but hillier routes. It may be that turning right around Tuzla would make sense, as in 2018, in which case Serbia might not be necessary.