Why Didn't We See The TVA In Spider-Man: No Way Home?
Spoilers ahead for "Spider-Man: No Way Home"
If you've been following the MCU lately, then you know things have been getting awfully multiversal. The lauded superhero-focused franchise has been building up and explaining the idea of parallel universes and timelines since it formally introduced the concept in the "Loki" series on Disney+. Originally, there is only one timeline, which is kept in check by the Time Variance Authority, a time-traveling bureaucracy that prevents the existence of any dangerous branches in the "Sacred Timeline." The TVA does this by eliminating "Variants," a version of a being who does not follow the path they're destined to follow and causes the temporal disruption. The TVA also eliminates branching timelines by removing all traces of the divergence and resetting a moment in time to when it is still part of the Sacred Timeline. In the Season 1 finale of "Loki," fans see the Sacred Timeline split irreparably when a Loki Variant, Sylvie Laufeydottir (Sophia Di Martino), kills the TVA's shadowy head, He Who Remains (Jonathan Majors).
While fellow MCU Disney+ show "WandaVision" also hints at multiversal influences, the issue doesn't come to light again until "Spider-Man: No Way Home." Everything goes haywire when a botched spell cast by Doctor Strange (Benedict Cumberbatch) and Peter Parker (Tom Holland) pulls in characters from the universes of Tobey Maguire and Andrew Garfield's versions of Spider-Man. Given the reality-breaking nature of this incident, the events of "No Way Home" beg the question: Why didn't we see the TVA come in to take control of the situation?
It's possible the TVA planned for this infraction
The simplest explanation for the TVA's absence in "Spider-Man: No Way Home" is just that this is another planned infraction. In "Loki," when Loki (Tom Hiddleston) questions Renslayer (Gugu Mbatha Raw) about the TVA's inaction when the Avengers are apparently allowed to mess with the timeline in "Avengers: Endgame," their actions are quickly explained away as events that were supposed to happen according to the TVA's plan. While this reasoning could also apply to "No Way Home," it admittedly seems like a bit of a reach considering Peter Parker and Doctor Strange's actions very nearly cause the fabric of reality to tear apart.
This theory makes sense when you take into account the fact that Doctor Strange and Spider-Man manage to resolve the issue before it completely ruins the timeline. As long as the multiverse isn't torn apart, the post-"Loki" TVA has no real reason to interfere. Of course, that doesn't mean there are no repercussions. As we see in the "No Way Home" post-credits teaser for "Doctor Strange in the Multiverse of Madness," some higher entity may be holding Strange accountable for the effects of his spell.
The TVA could have bigger problems to deal with
If the TVA — which still exists even after He Who Remains dies — isn't simply allowing Peter Parker to play around with the multiverse, it's also possible that they have more pressing issues. With the advent of the multiverse, He Who Remains predicts a massive multiversal war between his other Variants. This prediction proves true after Loki returns to the TVA to find that it has been taken over by Kang the Conqueror, a purely evil Variant, like He Who Remains. In the midst of the ensuing multiversal war (which we have yet to see), it's possible that the TVA simply overlooks Peter's actions. After all, it wouldn't be the only large-scale multiversal infraction occurring at that time.
This theory falls apart, however, if the events of "Spider-Man: No Way Home" takes place after Kang takes over the TVA. Assuming Kang's takeover also spells the end of the multiversal war, "No Way Home" would have to occur while countless multiverses are waging war, thus providing a large enough distraction to keep the TVA from interfering. At the end of the day, many of these concepts (e.g. the multiverse, the TVA, etc.) need a greater explanation to definitively piece together why exactly the TVA wasn't around in "No Way Home."
Hopefully, "Doctor Strange in the Multiverse of Madness" provides this as Doctor Strange and Wanda learn more about alternate universes than we ever knew before.