It's not adding roles/alt tags/etc. that's the issue. It's finding out that a screen reader doesn't support the ARIA markup (from the ARIA spec) that you are trying to use [1]. -- For example, using aria-describedby on an img doesn't work on most browser + screen reader combinations [2].
[1] https://www.powermapper.com/tests/screen-readers/aria/
[2] https://www.powermapper.com/tests/screen-readers/labelling/i...