[boltzmann-brain]

it's not just the aspect ratio - the perspective is different on curved monitors, because the surface is pointing in a different direction at every point. you have to simulate this with an effect related to the fish-eye lens.

[WorldMaker]

That's been my experience for the few games I've played with that had field of view settings with some semblance for curved monitors: things towards the far edges balloon larger like with a fish-eye lens, which turns out about what you need to best activate peripheral vision too.

[gigaflop]

When I game on my 3440x1440 curved monitor, I usually nudge my FOV 10 to 20 degrees higher. This gives me a very generous 'flat' zone in the middle for when (and where) I need precision, and the edges of the screen have a small bit of 'zoom' to help watch my corners.

Sometimes I try to game that a bit when looking at something distant: I'll wiggle the object's position between the edge and center of the camera, to get slightly different perspectives on it.

[boltzmann-brain]

peripheries bulge out because of a flattened perspective. Think about what you'd see on a perfectly flat screen that takes up the same /horizontal angle/ across your vision. Note that by necessity, it would be physically longer than a curved display that takes up the same horizontal angle.

One degree if vision is pretty narrow in the center of that, but much wider on the far sides.

Those games are not correcting the projection for curved monitors at all. The widening on the sides is just an artifact of projecting onto a flat plane, which then gets wrapped around the curved monitor in a simple manner.