Even at 7nm, a chip with 8 CPU cores, 80 Compute Units and all the caches will be gargantuan, with about 500 mm2 at the very least. 100$ per chip wouldn't even be enough to pay TSMC for the wafers, let alone make any profit for AMD. You can at least double the price for that just to make it covering the costs.
Also, just a 50$ NVME drive? If you really expect PS5 to be SSD only, then that's certainly not nearly enough. 80$ would be a better fit right now when buying in bulk.
As you can see, 400$ for your build are impossible, put at least another 100$ on top of it.
Finally, An Xbox 2 model being considerably less powerful than the One X doesn't make sense at all to me. I think it would at least match the One X in GPU performance, with the better CPU and possibly more RAM making the difference between the two.
No. Just no. So much wrong here.