Samsung C34J791WTR
3440 x 1440 pixels, 34"
Samsung C34J791WTR
3440 x 1440 pixels, 34"
Alternatively, there is the tool "Monitor Control":
github.com/MonitorControl/MonitorControl
This allows you to control the volume and brightness of the external monitor.
For me it worked like this: in the system settings under Sound, select the Output tab and select the monitor as the output device.
After that, it worked for me.