Switch boot stage 1 and no display,need help

Hello everyone
I have got a switch from my friend,he said it dead with Orange screen,and he sent to repaire but failed. now the switch cannot display anything, and no charging icon.I don’t have the repaire schema,I have read some topics here,
now the motherboard looks only wifi ic was being hot repaired,
I test the battery ,it has 3.8v, and I turned on the motherboard with only battery on
and test the voltage as picture,only have three 0v testpad there i had marked in picture,

  • I used the offical charger to charge, got a 15v,0.465a

  • the lcd connector around I had tested,no +5v and -5v

  • the max77620 voltage i had tested the stage 1 is ok. and no short,but no stage 2

  • the wifi ic 80% is broken,but i had test the wifi area capacitance no short

  • the max77621 below cpu output is 0.95v,the one left of cpu has no output

*now I don't have the idea of what to do next,need your help!*

if the wifi ic is broken with out 3.3 short ,will it cause the lcd no display ?

I have test the only motherboard with no battery by usb input 5v ,and got 0.2a.
I also test the motharboard with only battery by usb input 5v,and got 0.46a.
the battery test is 3.86v

now, I have no idea wher to start,
Maybe, I need to pull up the wifi ic first?

I had pull out the wifi ic and still no display no backlight. hope for help!!!