accessibility.psu.edu/math/mathml/

See provided screen capture video:

1. Does not understand fraction and square root in expression:
   m = (m0)/sqrt(1- v2/c2)

2. Replay looses selection. When user wants to replay current selection and clicks on replay (> after ||), then generic-combined reader looses selection and goes to the text after selection.

3. inconvenience: a side pane has to be invoked by "Menu/Settings/MoreTools/Reading Mode", 
   instead of just one-button click when user highlights the fragements of texts.

4. MathJax.js v2.7.0. A bit old.

The test conducted on Chrome
Version 152.0.7977.64 (Official Build) (x86_64)
usually, by enabling "Menu/Settings/MoreTools/Reading Mode"  

Annotation in Google seach:

The Penn State Accessibility MathML & MathJax Guide highlights the power of MathJax in creating inclusive digital environments.Why it’s great: Instead of focusing purely on aesthetics, PSU demonstrates how MathJax serves as a critical bridge for screen readers (like NVDA or VoiceOver) to accurately announce equations to visually impaired students.