Hi, I run into the same problem.
Have you maybe modified BIOS 211 to support M2 SSD as I did last week?
I have successfully modified BIOS v211 and tested Intel 660p 512GB NVME, today I got Intel 660p 2TB and I was changing BOOT order and after restart my G751JY doesn't start anymore.
I have also dissembled whole laptop, removed CMOS BIOS battery, removed RAM, HDD, SDD, nothing...
Did you resolved your issue at the end?
EDIT:
I just checked your video, and the difference is that mine stays ON, but screen doesn't turn on neither backlight.
I connected laptop to my TV via HDMI to be sure it's not VGA, but nothing via HDMI as well.