Eh. If they're trying to build this multiverse arc that will presumably lead to No Way Home and then culminate in Multiverse Of Madness, not having anything multiverse related happen in the Wandavision finale would be perplexing since what would be the point then?
Not to mention that there are folks online who absolutely despise the concept and absolutely don't want it to happen to the point of pettiness.
It would still feel like a huge copout if Evan Peters is not playing anyone of relevance after such build-up, so regardless of how you feel about it, that's not how a lot of fans will take it. There would be worse backlash than the Mandarin in Iron Man 3. And for good reason. Even taking all the superhero element out of the equation, it would reek of a contrived "gotcha" moment for the sake of subversion.