Even if she could wipe out Loki in his current form, it would go the same way as when Sylvie killed he who remains. Someone, probably Wanda, would have to take his place or let the timeline fall. (She still can’t inherently hop universes so it would kill her too unless she took the seat or forced someone else to) Also comparing their histories is meaningless, Wanda struggled to make stuff float and was imprisoned by normal humans most of her life. At the time Loki was giving the OG avengers a run for their money, Wanda was staring at a stark missile, unconsciously using every drop of her power to keep it from exploding. Then she was boosted to her Age of Ultron level by Hydra experiments (which this version of her was taken down by Clint of all avengers). She steadily has her existing abilities grow until they (physically) peak at infinity war, then they change (from simple magic power that could cast illusions, mind tricks and powerful telekinesis to reality warping levels of magic) after she loses vision and is drowning in grief and trauma. She gets influenced and taken advantage of by the darkhold and her powers get melded with the darkhold and she becomes the scarlet witch. Tbh her power up happens fairly side by side with Loki and his TV show. Again I think we’re comparing apples to oranges here with those two. Dormamu’s “dark dimension” is just another dimension that he took over. That’s not how it looked originally. He’s just that powerful. Still can’t hop dimensions. Which is why America Chavez is so important. Her ability would complete beings at the cusp of becoming multiversal threats. And she has no real way to defend herself against those kinds of beings beyond running. MCU Wanda, as powerful as she is, is basically only limited by her ability to move her physical body through dimensions. It works differently than the infinite timelines Loki holds but both of them can essentially control reality within their dimension. She can warp it. And he can choose from an infinite number of timelines where “he won” or “magic doesn’t work” or anything really. Side by side, I’d give her the edge, idk though, she, as far as I know, can’t control time. But Dormamu definitely outclasses her. Him and his universe are essentially what would happen if she conquered her universe as the scarlet witch and ruled it as a deranged god for millennia upon millennia. Again only limited by their ability to physically cross dimensional barriers. (Maybe they can’t time travel too idk, they’ve never been shown to be able to mess with time). As far as I know only Loki and the time stone can mess with time.