Hello,

First, make sure you haven't muted the tab, as it will mute all the sound. To unmute it, right click the tab, then see if it is selected to be muted.

If it is not muted, try disabling use hardware acceleration settings when available in settings.

"tab"? where in YouTube video? That's not muted. where else might it be muted?

If it is not muted, try disabling use hardware acceleration settings when available in settings. ???? where is thus to be found?

The tab on you tube is always un muted.

There is an option to block audio for all or selected sites.

Maybe worth checking the setting(s)