I don't know the exact premise of this movie aside from Strange looking into the concept of the multiverse. I'm guessing it had something to do with the part in Spiderman where all the people from other universe's were coming through to his (because they knew Peter's identity)?
But we saw in Loki when Sophie killed Kang, whatever he was dong to keep the multiple universes in place, stopped and the timelines were all being "unleashed", so to speak. The multiverse had already begun before the events of No Way Home.
They're all interconnected in some way and play minor roles into the bigger sphere of things. From WandaVision to Loki to No Way Home, I wouldn't say one particular character 'released' the multiverse as it was already there to begin with. More that they tapped into ways to breach into other universes if not alter them respectively.
We see Sophie's actions directly lead to...well whatever it is that happened. Her killing Kang ended the process, spell, stopped the technology, or whatever it is he was using to keep the multiple universes in check. It didn't play a role, it was the single most responsible event.
In No Way Home, we see Strange's spell tear a hole in space/time and pull people from other universe's. Since that was stopped/reversed, I'm guessing he or someone else does something that does it (or something similar) again in this movie.
They can't both be responsible for it happening.
I wonder if this movie will even acknowledge the events of Loki?
I bet they'll tie everything together somehow but it is interesting how they're balancing the events of their shows and movies. They need to acknowledge Loki soon though.
Although I think this movie is starting to sound crowded, I would welcome Loki. Connecting him and the events of his show to this movie would be a good idea.
It isn't clear yet how it happened, but the best guess I have is that the events of No Way Home were only made possible by Sophie's actions. Had she not killed He Who Remains, it's likely the TVA would have interceded and put a stop to the timeline jumping we saw in the film.
It's possible. It's all guesswork, because nothing has been definitively stated in a film or show yet, but my feeling is that the events of Loki created the possibility for chaos in the multiverse. From the moment Sophie kills He Who Remains, there is no longer anyone policing the timelines. I'd have to think that the TVA would intercede if a bunch of villains, and Spider-Men, were jumping between universes, so at least in theory, after Dr. Strange cast his spell each time someone popped up in the MCU timeline, a TVA agent would show up and bring him back where he belongs, and prune the branch that was created by the leap.
What I was trying to say in my original point was Strange couldn't have created/unleashed the multiverse since Sophie already did it. It already happened. It wasn't being managed or kept in check anymore. Two people can't make the same event happen. My previous post to you, that's the only explanation I can come up with. Strange's spell would have only affected "our" universe, but since the TVA wasn't keeping the multiverse in check, it pulled people who know Peter from ALL universes. That actually makes a lot of sense to me now.