It did not slow him down, if anything, it just made him worse. This was insane. It was clear that any head on (or accidental) attack wasn't the way to go, but containment was a good option. Offensive tactics weren't really her style anyway, it was always blitz or nothing, but defensive she liked. Defensive she could do.
Wanda strengthened her shield against the oncoming attack and, as he jerked back at Iron Man's repulsors, sent another hex bolt whizzing towards the monstrous doppleganger. The hex bolt spread as it reached him, arcing up and around him to contain him in a bubble of energy. She pushed more force into it to intensify it and then cut the cord, separating it from her energy source. The bubble was still under her control, but couldn’t drain her power. If he got himself out of that then they were really and truly in trouble here.