In Moodle playback rate does not work for Interactive Videos using videos uploaded in Youtube and has closed captions.
Issue is reported here: https://h5p.org/node/843205/
Test content: https://www.mathmusings.com/moodle/course/view.php?id=7 (login as guest)
Attached SS of browser console
Tested on the following browsers
Chrome Version 80.0.3987.100 (Official Build) (64-bit)
Firefox 72.0.2 (64-bit)