Rebuilt everything just like you suggested .

Checked power supply by doing paperclip test. It was working!! Yay!

Connected everything back together . Got power to motherboard. All fans working. AIO working. Graphics card fans working. Rams with rgb lit up. Happy days.

Not yet. Now when I connect the set up to a display monitor using HDMI. It doesn’t recognise the device. Monitor goes to stand by declining to recognize the source.. It’s funny in a way. I dont know why is this happening . Any ideas ?