Screen reader does not pick up text on page and alternative text box has a character limit

hi

It is a known limitation for Alternative text:

Alt text

Alt text (alternative text descriptions) are used to describe the appearance and function of visuals and images on the report page to screen reader users. Report authors should add alt text to every object that conveys meaningful information on a report. Providing alt text ensures that consumers of your report understand what you are trying to communicate with a visual, even if they cannot see the visual, image, shape, or textbox. You can provide alt text for any object on a Power BI Desktop report by selecting the object (such as a visual, shape, and so on) and in the Visualizations pane, select the Format section, expand General, scroll to the bottom, and fill in the Alt Text textbox. The Alt Text textbox has a limit of 250 characters.

https://docs.microsoft.com/en-us/power-bi/create-reports/desktop-accessibility-creating-reports#alt-text

and for Screen reader, I tested with chrome Screen reader, it could work, maybe your Screen reader version is support in power bi for now, you may submit it in power bi idea forum as below:

https://ideas.powerbi.com/ideas/idea/?ideaid=be6b40a1-16a6-40c7-826c-291b44a81dd5#idea-comments

Regards,

Lin