Hey, oh that's sounds terrible.
Regarding to bios, when you do a reset it should just work with default settings.
CPU fan works ? GPU fan works ? All cables connected ?
As I understand it you used all kinds of USB ports for your USB Flash Drive but none work.
Can you get a internal sata disk drive from that reseller or maybe you have one ? Than you can just burn a image on a dvd and see how far that get's you.
If nothing helps you could just take your build to a repair shop and let them take a look at it, since you have done so much already. This would not take long but probably cost a bit of money but than you know what wrong for sure and can just use the knowledge for all your other builds with the same parts.
Regarding to power usage your just about around the limit (+400W) and 3200Mhz RAM is not natively supported by AMD, limit is 2933Mhz.
Maybe this is the long way around, but can you install the SSD in a different/working PC and run the media creation tool on it? Then, when Windows boots and is working, swap the SSD to the new PC. Does it boot?