It is eventually revealed in WandaVision‘s final episode that Peters is not playing the X-Men universe’s Quicksilver, but another mysterious character entirely. With Agatha controlling this version of Quicksilver, fans began to suspect something was up, but the eventual reveal that it was a bit of trick casting on the part of Marvel was a big letdown for many. Peters was revealed to be a Westview resident named Ralph and not a Multiverse-hopping superhero as many people thought.
Now, it seems fans will have to wait until at least December, when Spider-Man: No Way Home premieres, to see the true beginning of the Multiverse. Wanda will then have to deal with that alongside the Sorcerer Supreme in Doctor Strange in the Multiverse of Madness. All of this portends big things for the MCU, but whether the stunt casting of Peters was a good choice or not is still being debated by fans. WandaVision ultimately proved to be divisive and Peters’ casting is one of the primary reasons for that, but the series sticking to Wanda’s personal journey seems to be the right choice in the end.
Originally from https://screenrant.com/wandavision-x-men-crossover-elizabeth-olsen-response/