I see but you still haven’t provided your inxi. Open your terminal and type garuda-inxi. Copy and paste what appears here in a code block like this.
~~~
Your output here
~~~
Also you mentioned you have tried everything on forum so I am just confirming but have you already seen this:
If you have already tried this then please do tell us where exactly do you get this error is your only source the brave browser or do you have some other apps not being able to play videos as well.
If it’s just the brave browser launch the browser from terminal and try to play the youtube video the terminal will generate logs. post that log here.