I agree with Brkdncr, this sounds like a video card issue.
I’ve had this problem multiple times before. The combination of display glitches and the fans spinning but no numlock or keyboard functionality simply points to the video card first.
In short, during POST of the BIOS it attempts an init to the display, fails and then stops attempting the boot sequence. It, the video card, is just as important during init as the motherboard registers, RAM and CPU all starting.
So, start with video, see if it works without the 5700XT and using the onboard or some other cheap pcie card. If that fails too, then it’s most likely the mobo as assumed. This just doesn’t sound like a mobo issue though.