For now, Dortmund is in a safe spot and I think by just keeping this kind of position I think they are good as long as they are not in the relegation and they are still in the line where they can compete with the Europa League, even though it is only with the group stage but it is quite good enough,
Darmstadt I think has no chance of getting up as fast as they can and evading Relegation they need to keep on dreaming that they are actually not getting into the 1st division again, but will surely get below the 2nd division
You said it " for now " Dortmund is on a safe spot , and i dont think that it will be that bad that they get into the relegation zone.
But if they want to play next season again in the Champions League they have to improve there playing and win games.
It was mostly disappointing what they have showed the last weeks in the German League and for that Darmstadt can be struggle them maybe.