A blank screen on a freshly built ByteBoi is frustrating, and it is usually a five-minute fix. In most cases it is a soldering fault rather than a broken screen.
Compare your board with the photo below and check two things. First, that no two neighbouring joints are joined by a blob of solder. Second, that there is no excess solder on the silver line that surrounds the PCB, as solder sitting across it can short the display.
Disconnect the USB cable and switch the console off before you touch the iron. Reheat any joint that looks bridged, and anything on the silver line, and draw the excess away with the tip of the iron or a piece of desoldering braid. Then power the console up again.
If the screen is still blank, send a clear close-up photo of both sides of the board to [email protected] along with your order number, and we will tell you what we can see. If the display is genuinely defective, the replacement is free.