After removing everything and putting it on a breadbox, barebones testing yielded the same thing - RGB lighting comes on but I still couldn't short the front i/o pins to turn the PC on. I even removed the NVME, RAM, separately and at one point only the cpu and cooler were installed. Still no luck .
I am assuming this might just be a MOBO issue? I am looking around for a paperclip to test my PSU. Beyond that, I am out of ideas
Sounds like you've exhausted all your options and pretty much done everything you could to solve the problem. Definitely sounds like it's just a bad board. Return it and get a new one.