If your interested, you might get some better results finding blind / low-vision playtesters and some useful feedback for your accessibility modes over by the audiogames.net forums.
Based off your trailer though, blind accessibility may be a bit of a challenge. Blind users typically don't use a mouse, in part because they can't tell where the mouse is on the screen without cues, so conventional FPS views are generally disorienting to them without something to ground them. Usually there may be some keyboard controls to snap the view to fixed compass points/angles, orient by fixed compass points, or to play with a fixed Y axis like in classic Doom, among other tricks. Keyboard inputs / audio cues for interacting with objects / inventory could also be a good idea, and audio cues for little things like bumping into objects / walls, 3D stereo positioning, etc. Along with TTS support or speech for any written dialog on screen.