Accessibility testing/engineering is a very important niche within software engineering. You could very easily build a career that will enhance the lives of others in similar situations.
It's quite hard for us, as we relay on browser extensions to test and tell us whether we are doing accessibility right or not, before we send the app to be tested by our co-workers/users.
These tools lack somewhat, they are not easy to integrate in the build process, and instead developers have to remember to run them, and check different things (e.g. there are multiple types of color-blindness, EU vs. USA regulations for accessibility, ARIA roles/labels where possible for screen readers etc).
So you could definitely start working on something in that area. Maybe more tools, more information, services for testing, consultancy.