If Madrid does end up in the play-off, I don't think it will be a big deal, but it certainly won't happen.
Although Madrid current performance is inconsistent, I have this assumption,
Liverpool vs Madrid (draw)
Atalanta vs Madrid (Madrid win)
Madrid vs Salzburg (Madrid win)
Brest vs Madrid (Madrid win)
If all the matches are in accordance with this prediction, I am sure Madrid will be in the best position to advance to the next round.
Looking at Real Madrid right now I doubt them, especially against a club that can be said to be quite good right now they will face Liverpool we see how Liverpool is right now with good strength and also consistent in achieving victory it will be difficult for Real Madrid especially away games Real Madrid is not like before we have to understand after Kroos retired they really lost an important figure on the field and in my opinion this Champions League is a difficult job for them Real Madrid of course Vinicius.
It's not just Liverpool who are having difficulties in my opinion Atalanta will also give a surprise to the Spanish team, I'm sure Gesperini will show his class when playing with Real Madrid and Brest is also a club that is difficult to beat in the Champions League right now I'm not sure they will succeed in these 3 matches with a win.