I think creating a new no_left_turn restriction, assigning the tertiary road as the via member, would achieve the intended outcome (https://www.openstreetmap.org/way/341551036). Another option could be to add a only_straight_on restriction from https://www.openstreetmap.org/way341551036 to    https://www.openstreetmap.org/way/78118539I. I wasn’t aware that no_left_turn’s were modeled instead along Ruta 8 trunk highway (https://www.openstreetmap.org/relation/6544446). With this knowledge, I am comfortable with whatever direction you take.