I took my MacBook Pro 16, year 2019, to a repair shop and the following was told to me:
During the measurements at the repair shop, it was possible to identify a region of the board heating up a lot, to the point of burning the technician's fingers when touching the area.
The component in question was the NAND, one of the data storage units on the logic board.
The NANDs are powered by some voltages, among them a voltage of 2.5 Volts. The circuit that creates this 2.5 Volts voltage, in turn, is powered by a voltage of 13 Volts.
The problem with the client's logic board is exactly this circuit that receives 13 Volts and, from there, creates 2.5 Volts.
Unfortunately, it is commonly observed in specialized Apple equipment repair shops that, when this circuit fails, it ends up creating a path for these 13 Volts that feed it to reach directly the NANDs, where the client's data, operating system, and other things are stored.
It was because part of these 13 Volts reached the NANDs that they died and are heating up in this way. The 820-01700 board often arrives at the repair shop with this flaw, and this equipment was no exception.