EDIT: ended up being 1 faulty ram stick, 1 (supposedly) bad psu, an overcooked cpu, a dead aio cooler and (potentially) a faulty psu. Thanks Linux bros.
I did the memtest. Figured out 1 out of 4 ram sticks are bad and sent it out on an RMA. Took the whole rig to a local shop and he load tested the PSU. It failed twice. He recommended I replace the PSU then the motherboard if I still had issues. So I replaced the PSU with a new unit, still the exact same issues. So I replaced the motherboard with a used one. Still the exact same issues. I updated the BIOS. Same issues but a new, more red Asus logo (yay).
I still cannot, for the love of AntiChrist, boot the thing. At. All. Not even from a usb. Attempting to fresh install windows and i have zero input from any devices.
I am at my wits end and I need my PC back up and running.
Linux bros blocked immediately.
Booting to the pre-install environment was the goal to finger obvious hardware/stability issues. Something that lands you on a desktop. If you want to try installing - whatever distro it was - check a guide for it. Fedora and Ubuntu are good places to start for both of these routes. They should require minimal configuration if you don't care about secureboot etc.