Yes, it is obvious that for Real to reach the final they need to win against City + Bayern/Arsenal. Individually, these tasks are quite realistic, but collectively the chance is reduced. I think that the overall probability of this is approximately 30% (by the way, the same as for the other teams from this thread towards the finals).
13-14 and 15-16 - those were good times, the two best teams from Madrid found out who is the strongest club in Europe (and the World)

For these Champions League predictions, I’ve assessed the chances of each team to be roughly 50-50 for virtually all the quarterfinalists. Although teams like Atletico Madrid and Dortmund may be less likely to reach the final, other teams appear to be in good form based on their performances.
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Do you think Atletico/Dortmund's chances are worse than Barcelona's? I wonder why? Atlético and Dortmund are playing each other, which means that no matter how bad they are, one of this pair will be in the semi-finals. Barcelona is playing with PSG and it seems to me that its chances (against the backdrop of a poor game throughout the entire season) are less than those of Atletico/Dortmund.
The draw worked out in such a way that in one half we have all the favorites (Real, Arsenal, Bayern, City) and in the other all the outsiders (Dortmund, Atletico, PSG, Barcelona), so in fact everyone has approximately the same chances of reaching the final.