Real Madrid will have to take this game serious, because they need these 3 points more than we can say, because if Real Madrid didn’t win the two last games, then I don’t think they will be among the teams that will be present in the round of 16 this season, which means they have no hope anymore. Although they have the highest chance of winning the game against Salzburg, it is a home game for Real Madrid, so it will be like a sure win for Real Madrid with no stress. Moreover, as you mentioned, Real Madrid is better than them in terms of strength and many other aspects.
The opportunity is right in front of their eyes, so Real Madrid will try to take advantage of this opportunity to open the way to qualify for the round of 16. With their performance improving and the front line showing its sharpness again, I think it will not be difficult for Real Madrid to get full points when facing Salzburg. Meanwhile, in the last game against Brest, Real Madrid was also the favorite team. Although Brest performed well since the first match, Real Madrid strength is still much stronger than them, only luck can make Brest steal points from Real Madrid.