It could be Iron Man. Since he was always the brains behind a lot of the Avengers' tech and strategies, he might be the one analyzing every detail in the trailer and coming up with plans.
In this fanfiction, perhaps the Avengers are watching the trailer together in the Avengers compound. They might start arguing about whether the events in the trailer are going to be good or bad for their world. Some could be excited to see old foes return, thinking it's a chance to set things right, while others might be worried about the chaos it could bring to the already fragile multiverse. For example, Iron Man could be analyzing the technology shown in the trailer, trying to figure out if it's something they can use or need to defend against.
One interesting plotline could be the Avengers having to deal with alternate versions of themselves that are brought into their universe during the events of No Way Home. It could lead to some really cool team - up and fight scenes.
Imagine the Avengers reading 'No Way Home' fanfiction. Loki would probably find it amusing and start plotting his own fanfiction - like twists in his head. Wanda Maximoff might be a bit emotional about it, relating to the characters' feelings in the story. Vision, on the other hand, would be trying to understand the concept of fanfiction itself and then make logical deductions about the Avengers' reactions based on their personalities.
Well, if the Avengers are watching 'Spider - Man: No Way Home' fanfiction, they might be looking for inspiration. Maybe they want to learn from the different scenarios presented in the fanfiction to better prepare for future threats in their own world. They could also be amused by the wild ideas and crossovers that often appear in fanfiction.
There's a fanfiction where the Avengers watch 'No Way Home' and it really focuses on how Doctor Strange's actions in the movie inspire Wanda Maximoff to further explore her powers. She sees how Strange manipulates the multiverse and starts to think about how she could do something similar with her chaos magic. It's a great read for seeing Wanda's character grow in new ways.
A really interesting fanfiction could be where the Avengers view the events of 'No Way Home' from a different dimension. They see Peter's struggles and decide to intervene in a more creative way. Maybe they use their connections across the multiverse to find a solution that doesn't involve as much danger for Peter. Some fanfictions also explore the emotional reactions of the Avengers to seeing Peter go through so much in this movie.
A different plot idea could be centered around the villains who were sent back to their own universes. What if some of them managed to find a way back to Peter's universe? And this time, they form an alliance, using their combined knowledge of different universes to try and finally defeat Spider - Man once and for all.
In 'Spiderman No Way Home', Peter Parker's identity as Spiderman is revealed to the world. This causes chaos in his life. He then seeks Doctor Strange's help to make everyone forget his identity. But the spell goes wrong and villains from different universes are brought into his world, like Green Goblin, Doctor Octopus, etc. Peter has to fight them and also tries to cure them instead of just defeating them. In the end, he makes the ultimate sacrifice and asks Strange to cast a spell that makes everyone forget him, including his friends and family, to save the multiverse.