Basically, I'm going to make a setup based off of a gaming laptop, and I wonder if I can use a G-Sync monitor with my laptop.
Only if laptop has Displayport out like this model.
https://www.razer.com/gaming-laptops/razer-blade
HDMI won't work because Gsync requires Displayport. Thunderbolt / USB type C to Displayport is possible but because this connection is usually connected to the igpu in laptops where the dGPU routes through, Gsync wont work. For Gsync to work, the video port needs to be directly connected to the GPU.