In Ant-Man and the Wasp: Quantumania, we learned that Janet met Kang when she went to the quantum realm, but that happened before the branching of timelines.
Does this mean that Kang existed before the events of Loki?
Time travel is a tricky business. The concept of “before” or “after” becomes meaningless when you can hop across different timelines or universes.
But if we focus on the cause and effect of the events, then we can say that events in Quantumania involving Kang the Conqueror and the Council of Kangs happened ("existed") because He Who Remains was killed by Sylvie in the finale of Loki Season 1. That was the trigger that unleashed the Kang variants into the multiverse.
This is confirmed by the post-credits scene of Quantumania, which features a cameo from Victor Timely, another Kang variant, who is also seen in Loki Season 2. Loki Season 2 acknowledges the events of Quantumania, as well as the aftermath of He Who Remains’ death. Loki Season 2 also shows that the TVA’s temporal loom can no longer control the branching of the timelines, which allowed the Kang variants to invade the multiverse.
Mobius: I guess one of 'em caused a little bit of a ruckus on 616 adjacent realm, but they handled it. So, we're all good for now.
- Loki Season 2 finale
(“One of 'em” refers to Quantumania Kang, “616 adjacent realm” refers to the Quantum Realm, and “they” refers to Ant-Man and company.)
So, in a nutshell, the events of Loki Season 1 caused the events of Quantumania, whose events are acknowledged in Loki Season 2. This will all culminate in Avengers: The Kang Dynasty.
According to Marvel Studios’ The Marvel Cinematic Universe: An Official Timeline, the events of Loki Season 1 happened before and caused the events of WandaVision, which happened before Quantumania. The book explains that with He Who Remains gone, and the TVA no longer maintaining the Sacred Timeline, the “doorways” (paths to other universes) are open. This makes a lot of sense and accounts for why the post-WandaVision MCU shows have so much multiversal madness going on — because Sylvie offed He Who Remains.
Fall 2023 | Darkhold Corruption
In a remote cabin, Wanda Maximoff studies the pages of the Darkhold that she took from Agatha Harkness. Its pages contain forbidden methods of traversing universes, and with He Who Remains now gone, and the TVA no longer maintaining the Sacred Timeline, the doorways are open. Wanda uses the Darkhold to pinpoint alternate realities where her sons Tommy and Billy still exist. Reaching them is still beyond her abilities, however, so she will need to find another with the power to puncture the barrier between realities.
In Loki Season 2, it is revealed that Sylvie used He Who Remains’ TemPad to send Loki to the TVA, but to the past TVA, before the events of Loki Season 1. In the past, there were statues of He Who Remains present in the TVA. And Loki heard a recording of He Who Remains talking to Renslayer, suggesting that the two were collaborating from the start.
Because of the time-traveling shenanigans in Loki Season 2, we can say that He Who Remains existed way before Loki Season 1. And Loki was actually in the TVA in Season 2 before Season 1.
Time Travel negates the meaning of before and after in the classical sense. Cause comes after effect and sometimes happens outside of linear time. So when you say "before" it helps to know if you mean from whose perspective. I'm going to assume you mean the audience.
From our point of view, albeit non-linearly, Kang already existed.
"Eons ago, before the TVA, a variant of myself lived on earth in the 31st Century."
The timelines had already branched once before and a multiversal war erupted threatening all of existence.
"The Peace between realities bwoooosh erupted into all out war. Each variant fighting to preserve their universe and annihilate the others."
Kang put a stop to this by creating the Sacred Timeline.
"Once I isolated our timeline, all I have to do is manage the flow of time and prevent any further branches. Hence, the TVA."
But Silvie undoes all of this by killing Kang and the previous status quo of the multiverse resets, and all the Kangs throughout time and the multiverse exist again.
From a storytelling point of view, all the films we saw up until Loki exist when a sacred timeline is still in effect. The past, the present, the future, all being controlled and managed by the TVA.
After the first season concludes, then the MCU proceeds as if this is no longer the case. The past, the present and the future no longer exist as part of a sacred timeline. Making that meeting with Janet and that particular Kang variant a possibility.
Again, before and after are relative when dealing with time travel stories. Janet may have met Kang in a flashback set in an era before the Loki series was made. But the events of Loki happen outside of that timeline. And the impact what can and cannot happen all along the timeline. Loki Season 1 doesn't happen "after" Janet meets Kang, Janet meets Kang because Loki Season 1 happens.