Using Loki season 2 both on their way and promising to explore the multiverse in more detail, there may be answers soon about whether or not there’s any truth in this idea. This theory could also provide the perfect setup for Kang the Conqueror stepping into Thanos’ shoes as the next big MCU villain.
The MCU’s phase 4 follows on from the decade-long Infinity Saga and the final defeat of Thanos. Ever since, the Spider-Man: No Way Home takes things a step further, as Doctor Strange breaks the multiverse itself. These stories see both Loki and Peter Parker meeting up with very different versions of themselves from other parts of the multiverse. It looks likely that these stories are setting the stage for the next big MCU conflict.
During Infinity War, Doctor Strange used the time stone to look through all possible realities to try and find a way to beat Thanos, and Endgame showed that their only way to do this was to use time travel. This feels contrary to what the TVA is doing during Loki, but He Who Remains explains to Loki and Sylvie that this was meant to happen. The Avengers' time travel was part of the sacred timeline that the TVA is intended to protect. But why? One way to explain this is if Strange traveled to the End of Time himself to meet up with He Who Remains and struck a bargain. After all, if Strange can make a bargain with a god-like primordial being like Dormammu, surely he could do the same with He Who Remains.
Ant-Man And The Wasp: Quantumania, not as He Who Remains but as the fearsome Kang.
As arguably the most powerful sorcerer in the MCU and the keeper of the time stone at the time, traveling to meet with He Who Remains is well within Doctor Strange's abilities. It also makes sense that he would be able to do so without anyone else noticing. Whether he stopped time while he was gone or he simply used astral projection to travel, no one is paying attention to him using the time stone until he's already finished. The question then becomes, what kind of bargain might Strange have made to stop the timekeepers from intervening during Endgame? Whether or not this theory turns out to be true, the multiverse aspect of the MCU is certain to develop further during Loki season 2 and Doctor Strange: Multiverse of Madness.
