If websites could be made accessible from the installation of an overlay (e.g., AccessiBe, UserWay, etc.), wouldn't the DOJ (the regulatory and enforcement agency behind Title II and Title III of the ADA) have mentioned overlays / widgets / plugins / software / apps in their "Guidance on Web Accessibility and the ADA" post?

https://beta.ada.gov/resources/web-guidance/

Even the resources listed in the DOJ's resources page don't mention overlays.

Transcript:

https://adabook.com/can-overlays-accessibe-make-website-ada-compliant/