Use a Unicode font for default bullets
Currently, Word's default font for bullets (both from the control panel utility and paragraph styles) is the Symbol font.
The Symbol font is not Unicode, and therefore can't be used to make accessible documents. The default bullet on it, Symbol 183, is not recognized by screen readers and other assistive technologies, causing accessibility errors.
Instead, reprogram the default settings that ship with all versions of Word to use a Unicode bullet (U+2022) on a Unicode font, such as Segoe or another Unicode font that you will guarantee will be available for years to come.
Unfortunately, Microsoft removed the incredible Arial MS Unicode font from Windows in 2018 due to a licensing issue. It would have been the perfect font for this purpose. See discussion at https://word.uservoice.com/forums/304924-word-for-windows-desktop-application/suggestions/35794192-microsoft-has-billions-in-profits-please-re-insta