To control a muted video (i.e., to unmute it), you need to enable “Show Controls.”
Without visible controls, it’s not possible to manage playback from the frontend.
By default, Firefox blocks videos from playing with sound. You’ll need to manually allow it in the tab settings—please refer to the attached screenshot.
Also, in the current setup, if both loop and autoplay are enabled in the video settings, autoplay may not work as expected, In that case, You need to mute the video, It's browser standard.
Thank you for your understanding.