It's hard to tell just from the grainy picture. Is the screen lighting up (glowing) if it is the backlight is working so that would remove the backlight flex issue.
Does the screens image change in any way moving the lid up and down or connecting or disconnecting the HDMI connection? If not then I would say the T-CON has an issue or the connecting to it. This is a different cable than the LCD cables which compose the image within the LCD. Do you have any damage within the Chin plate which sits just below the displays image area? That would be the LCD cables being damaged.
And lastly you didn't have a liquid spill or place the system down on a wet surface as the back hing area is quite open and wouldn't take much to get into the T-CON board.
In any case the display assembly would likely need replacing MacBook Pro 16" (2019) Display Assembly and here's the guide MacBook Pro 16" 2019 Screen Replacement
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