Despite their immense power, Marvel sorcerers like Scarlet Witch have a secret weakness that few villains have truly taken advantage of. In mainstream comics, there's a sense in which magic has always seemed like something of a "Get Out Of Jail Free" card. Major comic book publishers like Marvel and DC have never formalized the basic rules of their magic, meaning writers can basically use sorcery to accomplish anything they wish. It's not uncommon for powerful sorcerers like Doctor Strange to turn up at the end of an arc and deal with a cosmic crisis with just a simple spell. It's not always satisfying in narrative terms, and is worlds away from the carefully sketched rules of power present in other corners.
The Marvel Cinematic Universe seems to have recognized the potential for this problem. In WandaVision, Scarlet Witch learned of magical runes that could be cast over an area, meaning only the sorcerer who cast them can use magic in the affected area. It's an effective weapon - one that could still be used to strip even the most powerful Masters of the Mystic Arts of their abilities. These runes serve to level the playing field, restricting the potential of magic and making the story much more interesting. However, Marvel's original take on the power-deadening magic circle has an added element that's way darker.
There's actually an equivalent in the comics themselves, though it's significantly darker. In Runaways #17, by Brian K. Vaughan and Adrian Alphona, the Runaways' Nico Minoru went up against a time-traveling villain who'd faced sorcerers before. She didn't realize he'd set a trap - a circle of wizard's ashes that neutralized her powers. Apparently it only works on specific "brands" of magic, presumably referring to the dark magic of Nico's Staff of One. Other Marvel sorcerers use similar dark magic, including Doctor Strange, so it's likely they share Nico's weakness.
The Original Spell Calls for a Dead Wizard
It's unclear quite why a circle of wizard's ashes has this effect on Nico's magic. Presumably it's because Nico's type of magic draws on her life force, and the ashes have a literal "deadening" effect on such witchcraft. Still, it's a striking weakness shared by the most dangerous sorcerers, and it's easy to see how it could be used against the Scarlet Witch, whose Chaos Magic is the definition of dark magic according to Marvel lore.
As dangerous as this technique is, it hasn't seen much use since it was introduced. The difficulty of obtaining a wizard's ashes is one explanation, though the constant reinvention of Marvel's magical rules is a more likely culprit, with no theory of magic tending to survive more than a couple of new creative teams. Hopefully some of Marvel's writers will recall this dark take on Scarlet Witch's MCU weakness however, and choose to use this dangerous magic to level the playing field again in some upcoming adventures.