i cannot set the settings to 4k 60hz because as soon as i set one of those the other drops.
You’re using Windows right? Are the AMD display drivers correctly installed? Otherwise that could explain that behaviour.
my monitor is benq ew 2780u which does support 4k 60hz and i have tried multiple hdmi 2.1 cables so I really am not sure what to do
If the Windows drivers are double checked and as your Benq EW2780U monitor also support DP and USB-C input sources you could try any of those connections instead of the HDMI and check if it helps.