Zephyrus G14 2023 4060 (GA402 XV GA402XV) - Can't connect display via left USB-C port

[Poortasa]

Hi,
I just got a G14 today. I have been trying to connect my external monitor to the left USB-C port (which I believe is also the USB4 port) ; so far I get no signal and only a connect-disconnect sound in Windows. Also the OSD shows that I go into usb power delivery mode and then gets out of it (all the while I am on AC power already)

I was able to connect to my external display with an adapter (USB-C to DP) and the port seems to work fine.
Also tried the right port and it works fine and also seems to connect through the dGPU.

Also tried the same usb-c to usb-c cable with another G14 from 2021 (5800HS-rtx 3050 ti) and its left port worked fine and gave me 1440p up to 144Hz through the dGPU (the cable is USB4 certified and supports up to 40Gbps but the older laptop's port was 1.2DP I believe) 

Weirdly, the same port works with a different monitor (1440p 60hz only). So it's not a matter of having a port with no display output.

I found a similar issue with last year's model here which was resolved after a BIOS update.
Anyone had a similar experience? Is there any way to get in contact with ASUS regarding this problem? 

[Poortasa · Accepted solution]

Updating this to add new information. Two or three BIOS updates did not change anything but a new firmware for my monitor (M27Q-P or M27Q Pro) which was released on August 14 2023 solved the issue! now the display port on the left and right BOTH work without a problem. 

So it seems like the problem was the monitor and not the laptop. I realized this a month ago when sometimes the USB-C port on the monitor stopped working altogether (even had no power) and only solution was to re-plug the monitor. Weirdly the monitor firmware update did not state any changes other than "Timer" fixes.