Issue connecting to my 144hz monitor

Hi, I’m trying to get 120hz by using a USB C to DISPLAYPORT from my Razer blade stealth 2019 to my external monitor (optic mag24c). Every cable I’ve used displays flat colors onto the monitor as seen on the video I’ve attached.. usb c to hdmi works fine on 60hz but if I change to 120hz, the monitor flickers constantly. Any suggestions to fix the problem would be great, thank you.
my blade has the Intel 10th gen i7 and gtx 1650
I've tried the razer care support and they are no help