Gpu is on the backside, riser fed. (might want to do some research on that riser, just saying)
The H1 is a semi pre-built, comes with a 140mm aio and a nzxt sfx-l 650w 80+ gold.
Actually, we'd need your assistance first. It's like the wife saying the car won't start. That's all well and good, but knowing exactly what Is happening tells us more than what's not happening.
Is the fans spinning up, are the 4 debug lights sequencing or getting stuck on 1 in particular, do you have the USB-C plugged into the board, does it come on then immediately shut down requiring you to unplug the pc.
Stuff like that is needed to see exactly where you are at.
If you watch the next vid GN did later, the fix is almost as bad as the original nylon screws. The problem is the 12v plane is far too close to the screw hole, so any subsequent messing around with that screw, be it nylon or metal, wears away at the pcb and the 12v plane becomes evident. You get a direct 12v to ground short and that's where the fire happens.
The 'fix' is a band-aid on a cut that needed stitches. The riser should have been recalled and resigned, giving a much wider skirt around that hole. Both holes.
Edit: And NZXT has responded with just exactly that, see video below.