There is logic within your logic board which powers the backlight LED’s within the display. While its possible that has failed. This series mostly had the FlexGate problem like the 13” model.
Sadly, Apple never fessed up about it on the 15”. It was less of a chance than the 13” models and it often happened on systems like yours! The display sitting around 45º angle as that was the high stress point on the cable.
Give this a view [https://www.youtube.com/watch?v=OqHUYNZVLfM|MacBook FlexGate Fix / Repair: What if the cable is +3mm longer?]
In any case I would find a good MacBook Repair person who knows these systems at the deeper level to check if the cable is the issue or if the backlight power circuit needs repairs.