Asus tuf F15 wont launch unless i will unplug my screen & Random black screen mid-day

[Guynoren]

Hey guys, recently i bought an asus 240hz fhd to pair with my asus tuf f15 gaming laptop.
I am pluggin it with Display port ( screen ) to Usb-C ( laptop ) in order to get the g-sync going and fully 240hz support.When i am turning on my PC while the screen is plugged i can see the pc has power but nothing is showing - neither on external monitor or laptop's screen.
When i am unpluggin the screen from the laptop, the ASUS Logo immediatly goes on and the laptops launching. then i am plugging back the screen and all good for the rest of the day.

Moreover, While studying / playin games the monitor goes randomly black for 2-3 seconds ( Without the screen showing display port no signal + there is no disconnection sound from the headphones ). 
I tried already to remove nvidia driver with the DDU tool and re-install it. 

Any ideas 🙂 ?

[Guynoren]

I will also mention that i connected the HDMI to HDMI and it worked good ( But i dont get the g-sync feature ) 
and i will also mention that i connected the DP to USB-C ( the thunderbolt, not the g-sync one ) and it worked good
Can it cause issues because the g-sync one disconnects? shouldn't i hear a disconnection sound / the monitor will present that there is not signal?
Is there a possibility which the igpu and dgpu are switching for a few seconds?