It's possible that the issue you're experiencing with your Aorus 15G's HDMI and DisplayPort ports not working could be due to a problem with the motherboard. However, before concluding that the motherboard needs to be replaced, there are a few steps you can take to troubleshoot the issue:
Ensure that your external display and cables are working properly. Test your external display and cables with another device to make sure they are functioning correctly.
Update your graphics card drivers. Visit the manufacturer's website to download and install the latest drivers for your graphics card.
Check your Windows display settings. Make sure that your external display is recognized by Windows and that it is configured properly in the display settings.
Reset the BIOS. You can try resetting the BIOS to default settings by accessing the BIOS menu during startup.