You more than likely damaged the pwr in part of the motherboard. Most modern laptops use lead free solder and this is prone to mechanical cracking.
Modern BS. Solder joints only rarely cause issues. Even for BGA GPUs, where that BS myth originates from.
Did you miss the part about the laptop having been dropped? Depending on what it landed and how, parts could literally have been sheared off the board. Or solder joints cracked. Sometimes all it takes is one SMD resistor to get knocked off on one side and and nothing works - like an I2C pull-up for the battery management.
So while I agree with you in general, in this case, when the machine has suffered a mechanical shock, a cracked solder joint is a very real possibility. Of course, that doesn't mean taking out a heat gun but carefully inspecting the board and checking the charging circuitry.