I tried turning the Messenger's notifications on and off but it still gives that "ding" sound. It gets annoying if you are watching something.
I may have not tested or browsed all options thoroughly as I just jumped in on Opera GX yesterday. Please let me know if there is a way to do this.
I would still love to get notifications but it can be on mute and just give out that red dot to know that you have a new message.
Thanks!