I found a pretty good way to handle this: I switched to a "source" view which is the first-person view without rotation and foreground stuff. So it looks like you're still looking out of the person's eyes, but also not really because it ignores the head rotation. This makes it way easier to handle for me. The real panel references the source view with rotation and foreground things. References are updated live, so I immediately see how the end result looks.
I have a better idea for the prologue to tie it more together with the main panel, but for now I'll work on the first-person view. It's way too uncommon even in TF art (probably because it's difficult as fuck )
It would be really cool if Affinity Designer had a gradient blur filter to make an object blurry on one end and have it become sharp on the other. Fading a blurry version over the sharp one is a possibility with the current tools, but it will look off
I said I wouldn't use an internal monologue (because the character has lost the ability to use words not just physically, but also mentally), but vocalizations are fine and help a lot.