Don’t think there should be anything wrong with my PC as it’s a completely new PC I just bought.
I highly doubt it’s an issue with the DP cable as I just got new a one but still same issue.
New doesn't mean it is good, as you can attest to. A new cable is just that, new. Linus did a test on a bunch of his cables, some new in packaging and found half of them had issues passing the test, and many failed completely. Surprised him that so many, especially the 'default' freebie factory cables were basically junk, as were many off-brands.
It's better to not assume anything until proven. DP can and does have issues sometimes relating to pin#20, sometimes it fails due to voltage differences and you do not get the 'handshake'. Basically meaning the gpu sends a signal to the monitor, but the signal dies somewhere between the ports, so the gpu can't turn on the monitor. Like knocking on a door, but nobody home.
You can try hotbooting the DP, turn on the pc but unplug the DP from the gpu prior. After the pc hits the post stage, plug the DP back in hot. Many times this'll act the same as plugging in a USB, forced handshake.