battery voltage test with multimeter

iPhone 6s turning on while plugged to power but not charging

No service - No sim , antenna damaged could it affect it?

backlight working for 1 sec after turning on then goes black

Does changing the Power IC affect the data?

from where I can find the schematic for iPhone boards?

phone dropped , changed Power IC , worked but data lost?

if I put the laptop in sleep mode it shows a white screen when turning

doesn't charge , used different charge port , still same problem

Not working although there is a current indication from power supply