Aurora R12, AW2521FA, no DP signal

I bought an Alienware AW2521FA gaming monitor and from the first use, I ran a performance test on my computer and when it got to 3D graphics I got a black screen the no DP signal then the monitor went in standby. The only way to make it work again is reseting the computer. I thought it is strange and maybe a bug from that software so i started using it and it continued to do that randomly, while playing a game or while simply being on desktop. I tried everything. The problem is that it works on lower Hz like 60, but as soon as i go to 144 or 240 it does this in a couple minutes. I also tried with the hdmi cable and i get the no signal message. I tried updating all or my drivers and firmware and it did nothing. My computer is also an alienware, with a RTX 3080 graphics card. I also tried changing monitor settings then going back to factory settings and i also used gsync but it is still the same. I cannot use the monitor on mor than 60 Hz. So i contacted dell and told them about the problem and they sent me another monitor, but rhe problem is the same. Today i tried to do another update to my graphics card drivers and as soon as it finished i got the no DP signal again. Can anyone help me? I am not able to use the computer and shutting it down from the button so many times becomes really scary because it might affect some of the pieces.