This adds options to control audio playback speed in the reviewer.
You can configure the shortcuts and the speed change from the add-on config under Tools > Add-ons.
There are several add-ons on AnkiWeb that do the same, but it appears that none of them works on the latest versions of Anki (2.1.49+).
This only works with the mpv media player (which Anki uses by default on all platforms).
AnkiWeb page: Audio Playback Controls - AnkiWeb
GitHub repo: GitHub - abdnh/anki-control-audio-playback: Anki add-on to control audio playback speed