The closest you could get to building your own laptop would be to build an ITX system and put it in a small box with a big battery. Basically, there's no sensible way to do it.
OS: Windows 10 64 bit Professional
CPU: AMD Ryzen 5900X
RAM: 48GB
GPU: Radeon 7800 XT
CPU: AMD Ryzen 5900X
RAM: 48GB
GPU: Radeon 7800 XT