This is a common problem that happens on Brave. If I’m watching videos on any site, and I get up to leave for about 10-15 minutes, Brave somehow kills audio for me, not just on the browser, but also on the PC.
This means that if I don’t get audio on Brave, I don’t get audio on my computer to work. If I open VLC to watch a movie or listen to music, I don’t get audio unless and until I close the tab in Brave of the video whose audio I can’t hear and reopen it until the bug resolves.
This is a very irritating bug. It can be resolved easily by closing and reopening the offending tab till audio finally plays but it’s very inconvenient as a whole.