Yeah I’m thinking that the person Bettany referred to is himself. It just fits, especially since he said something like “it’s someone I’ve known my whole life.”
Also, I’m REALLY digging Vision’s all-white look. I hope that’s the version that survives because it just looks cooler than his original look (which I also love).
I think there might be some other reveal though around who or what made Wanda do this. The deed from Vision just seemed suspicious. Maybe I missed something but it just looked like it just appeared on her car seat and she didn’t know anything about it. Vis had been dead for five years at that point so he couldn’t have left it there recently. Perhaps he left it there and then they went off to Wakanda together to fight Thanos and now that she’s re-emerged, she just noticed it. But it still seems a bit questionable. Maybe Hayward or one of his SWORD agents snuck it in there with the goal of luring her to Westview for some reason, or someone else did.
I think it’s also possible that “the Scarlet Witch” is an actual entity separate from Wanda that she can control with practice, but right now it’s actually controlling her without her realizing it... something similar to how Parallax controlled Hal Jordan and drove him crazy. If so, then that would be the real villain and by the end of the series, Wanda will tame or destroy the sentient portion of that power so that nothing like this happens again. I’m leaning towards that actually, because I feel like after the big Agatha reveal, it would feel cheap to suddenly be like, “But wait! There’s someone else who was the REAL villain all along!” and have Nightmare or Mephisto show up.