Question Not posting anymore

[Latreia]

I built a pc for my mother:
ASUS z390-i
I7-9700k (using iGPU)
Corsair lpx ddr4 3000 2x 8gb
Samsung 970 pro m.2
Be quiet 500w sfx psu
Silverstone sg13

I had it plugged into my sine wave ups when building, plugged into my 1080p TV via hdmi, and plugged into my wired USB mouse. Thinking back, after finishing the build I tried plugging it in to my 4k TV in another room with a surge protector, and saw the issue. I brought it back into the computer room, and it booted.
I hand carried the pc during my flight to her. Now that it's here, plugged into her 720p and BT mouse keyboard, it booted once and after shutting it down, it will no longer post.
Rgb lighting and power led come on; Cpu and psu fan spin; case fan spins once and then stops; mobo troubleshooting lights don't go through the process (checks cpu, dram, etc). I've reset the cmos and I've reseated all of the connectors/dram. I've tried a wired keyboard with no change. The only thing that's coming to mind is that the PSU needs the clean power of the sinewave ups... But could it be that wimpy?

 

[Latreia]

It turned out to be a grounding issue with the motherboard.