Defeat and victory are not about fear or courage of a club against one opponent, but it often leads to fatigue of the players and also the wrong tactics used by their own coach. So what you said is also true where Madrid might need something else including rest to make a more mature evaluation in undergoing the second leg later. I also often see difficult comebacks from Real Madrid in previous seasons but it was done very well by Real Madrid, but for this season I personally also see it will be much more difficult for Real Madrid to make another extraordinary comeback in the second leg.
Because Madrid is currently in a situation where they have weaknesses in defense, the situation is definitely different from previous seasons. Ancelotti has no other choice but to play with full strength to play aggressively. If the difference is 1 or 2 goals maybe they can still play calmly, but with a difference of 3 goals, of course, they will have to control the match to get more opportunities. Just hope Madrid's defense can play better. If not, Inter will still have a chance to score goals.
Real Madrid's chances are very low now. Ancelotti should be aware of this and will take precautions accordingly. He is one of the best managers in the world. I am sure that Arsenal will prepare well for the return leg. I think Arsenal will defend. If they continue to keep the score, a goal against Real Madrid with a counter-attack will allow them to advance to the next round. The match they will play in Spain will be very difficult because Real Madrid fans will put Arsenal under pressure, but Arsenal will still defend as best they can and advance to the next round.