Adobe Experience Manager (AEM) Designer is used to create PDFs, HTML sites, or Adaptive Form sites. While AEM does have some accessibility features built in there are bugs and feature gaps in version 6.5.
I have been working with Adobe to address both the bugs and Accessibility feature gaps over the past year and in May 2022, they will be releasing a comprehensive update including fixes for the bugs and gaps plus more features.
To answer the question, in the 2022 2nd and 3rd quarter releases, AEM will stack up very well with fixes for PDF garbage collection, image artifact, and more plus Accessibility feature gaps such as adding more Accessibility Roles to cover List structure, hyperlink structure, and Table structure.