SPOILERS for WandaVision through Episode 7, because I want to get some wild-ass theorizing out there before all is revealed.
In the Marvel Cinematic Universe, movies like Thor and Doctor Strange established magic as a technology born of a more advanced science, a means of tapping into primordial cosmic forces. The Infinity Stones, created along with the universe by the Big Bang, are powerful sources of these energies. But possessing an Infinity Stone is not the only way to access a portion of its power. Wanda and Pietro Maximoff were given powers by Baron Strucker, experimenting with the Mind Stone. Carol Danvers got her powers from an explosion of an engine powered by the Space Stone. Some mortals in the MCU seem less accidental about tapping into these forces.