No Power - Motherboard Issues - Soldering Repair

I bought an Asus ROG Zephyrus S GX531 that was deemed "broken - needs new motherboard".

The old owner sent it into Asus and the repair for this now sub $1000 laptop would be $1200.

I thought it would be a good idea to take it apart and see if anything stands out to me. I'd love to get it working if possible.

From what I have tested, the power supply, power button, battery, and CMOS are all in good health. The issue is definitely with the board.

The thing is, I don't know how to diagnose it from here. How do I go about finding the faulty part of this motherboard? I had worked on quite a few Asus laptops, and most of those that don't turn on had board issues. I never found out what part it was with them, just the motherboard in particular.

I'm hoping it's a common issue and someone can point me to the best place to check, or can help me find the best way to diagnose it.