RAZER blade 15 base(2018)4k External Display Refresh Rate issue only 30hz

Hi guys,

I have recently bought a razer blade 15 PID:RZ09-02705E76 days ago. Currently im experiencing a very unusual issue with my 4k external display's refresh rate.

So currently my external display (LG-27UD88) is connected to the HDMI port of my notebook, i have checked both ports it supports HDMI 2.0 (which means it can carry 4k@60hz). My cable also is HDMI 2.0. But when i selected the 4k resolution 3840x2160, the refresh rate available is only 30HZ or lower. I did some testing and tried to disconnect the hdmi port and use the usb-c port instead (since my external display has a usb-c port). It actually can go up to 60hz in 4k, but the only problem i have here is that i cant play any games because the usb-c port utilizes the intel graphic card, so i have no choice but to use the HDMI port instead.
The highest resolution available that can run 60hz when using hdmi is 2560x1440. So for a workaround, when im not gaming ill use the usbc connection to the display and when gaming ill use the hdmi connection but tone down the resolution one step back.

Is there anything i can do to solve this issue? Because im not planning to do this forever its kinda inconvenient.