There are a lot of people with disabilities on iNat. Here are a couple of threads, although these tend to be about difficulties out in the field, not so much about using the site:
https://forum.inaturalist.org/t/inatting-nature-hikes-while-injured-handicapped/7568/7
https://forum.inaturalist.org/t/deaf-and-hard-of-hearing-naturalists/46829/3
https://forum.inaturalist.org/t/neurodiversity-and-inaturalist/17268/139