Wanda's hands power up - which should not be possible within the sanctum. It would have to be part of the illusion.
Plus, as we saw in her origin - Agatha's shtick to take down other magicians is to let other practitioners fire at her, and then to use that channel to corrupt and draw out the opponent's energy until they are a withered husk. Agatha may be trying to do that again by making herself a huge target. If so, boy is that going to be a mistake. Sure, Agatha, drink from the fire hose. That'll work out well for you :/
My impression was not that this was a deliberate ploy on Agatha's part — she certainly doesn't seem happy with being assaulted the way you'd expect a villain with an absorption power to be. You'll also note that the charge leveled against her by the coven is "stealing magic above her age and station" and "practicing the darkest of magics" – nothing about what she actually
did with the magic. If you'll allow me to provide an alternate interpretation of Agatha:
Young Agatha is a talented witch, and is taught by a coven of several witches including her own mother. She comes across some sort of Forbidden Knowledge and learns it, and the coven is aghast and terrified of her power. They likely believe that even if she hasn't done anything really bad
yet, the Forbidden Knowledge will corrupt her, and decide to kill her before she becomes a threat they can't handle. You'll note that during the trial/execution, Agatha exclaims that she "cannot control it", and begs the coven to teach her. When the beams turn purple and start draining the coven, she looks
surprised. Before her mother makes her final attempt on her life, Agatha begs her "Please, I can be good", but her mother rejects the possibility and attacks, sacrificing her life in vain. (As a side note, during this final attack there is a magic manifestation similar to a crown or tiara on Agatha's mother's brow, not entirely dissimilar to the headdress Scarlet Witch wears in the comics. I do not believe this to be a random coincidence, but I'm not sure what the meaning is - perhaps Agatha's mother was linked to some "opposite number" of the Scarlet Witch or something). This is what we know.
And sure, it's easy to go from there to assuming Agatha's goal with coming to Westview is to acquire Wanda's power. But I think that would be too easy. I could easily see young Agatha deciding to prove her mother wrong, by deciding that she
can be good, and to also take it upon herself to seek out practicioners in similar situations and aid them and teach them (and possibly deal with them if it turns out they're too far gone). So, 230 years later, she detects an immense burst of magic over in New Jersey, and decides to investigate. She wards herself against the hex, and infiltrates it. She does assorted mischief, poking and prodding Wanda to see what's going on. As she can't figure it out, she resorts to summoning some form of simulacrum of Pietro, but apparently grabs/copies one from an alternate reality, and has him try to learn what happened from Wanda. Fietro pushes too far and Wanda rejects him, violently. So she decides to up the ante even more by kidnapping Wanda's children and use them as leverage to make Wanda show her her background, which leads Agatha to conclude that Wanda is the Scarlet Witch.
At this point, I believe Agatha sees herself in Wanda – a young witch with far more power than craft, one who doesn't even know how to create a sanctum. And yes, Agatha probably sees Wanda as a potential threat, but also as someone with a good heart, and someone who could be taught to do great deeds with that power.
Of course, Hayward's probably going to screw that up by sending in White Vision and mess with Wanda's stability even more.
I think the aspect ratios may be less about the physical location, and more about its relation to Wanda's state of mind. The sanctum and outside the Hex are reality. Wanda's mind is in reality now. Basically, the aspect ratio is "stuff got real".
Could be, but they've generally been pretty good about cinema = real world, regular widescreen = inside the hex. The only exception I can remember is the hex's expansion, but that could be because changing it during the "axiom wash" would draw attention to it and look REALLY weird.
Edit: it also takes a while to catch up when Monica pushes through the barrier, and doesn't start changing until she gets her bearings and start running inward.