I've been using the new Mantis armor a lot lately with a daggers build, and one thing I've noticed that slightly bothers me is that there is no way to disable the overlay effect of the gas mask or the sound distortion from it. I personally think this would be a nice little QOL feature that could be added to the settings menu or, perhaps, even to the armor itself, via making it a toggleable option on the armor, creating a slightly different appearance, or by creating a different version of the helmet that can be crafted.

Agreed. I actually don't really mind the audio change, but I don't like the vignette/haze overlay. I can even understand it with the regular gas mask to some extent, as it's a task-specific mask which has no set of its own, but the Mantis Armour has a set bonus, like the other sets. I don't think you should have to put up with the view restrictions to wear the full set in first-person.