Board Thread:General Discussion/@comment-26838855-20190803131136/@comment-1894786-20200104033944

In the comics, the Dark Dimension is known as a patchwork dimension, comprised of various planes of existence conquered by the Mhuruuks.

Doctor Strange's film establishes that Dormammu constantly hungers to expand his Dark Dimension by taking over other universes, like he tries to do with ours in Hong Kong.

We can reasonably assume that the Dark Dimension we see in Doctor Strange, the Darkforce Dimension we see in Agent Carter, the Loa Dimension we see in Cloak and Dagger and the Dreamland from Runaways are simply all just different parts of the larger world.

As for the time travel, as Marvelus posted earlier in the thread, Mordo warns against branched timelines (Endgame), time loops (Agents of SHIELD) and rewriting history (Runaways) as possible outcomes of messing with the time-space continuum. And we see history rewritten in a localized space (Strange saving Wong from death), as well as time loops (the "I've come to bargain" scene) in the movie itself. The movie future proofed the MCU unintentionally when it comes to other methods of time travel.

While yes, scientifically Bruce is 100% right, and actual real life time travel would just cause branched timelines, this is fiction and thus everything can be a little more unpredictable according to what the writers want.