I'm using a Samsung S34J55X ultra wide monitor which goes up to 75hz. When I connect it through DisplayPort (as it was instructed) the monitor turns on and off when I switch on the lights or when the fridge turns on/off . If I switch to HDMI 2.1 , the problem stops but the monitor only displays 45hz instead of 75hz. I have used several "protective" sockets and using a UPS as well. Nothing has helped. How can I solve this without going down to 45hz?