Nintendo Switch Lite has Backlight but no Display

I have a nintendo switch lite here with no display after I repaired it. I have no clue what could have went wrong, but I need help.

I got it with bluescreen. So first i reflowed the CPU, it seemingly worked, but I had no display (backlight, touchscreen, everything else seems to work fine). I took the CPU down, reballed it, just resoldered it, but still no display. Everything else works, I have all the keys (they make a sound), well sound, touch works and backlight. The switch charges as it should.
What can I do? Maybe flux in the connector of the screen, but i flushed it with ipa several times. Under the microscope i see no damaged pins.

What now? What should I check? Please help

I did some measurements:

I bought and tested with a new display, still just backlight. So it is a problem on the mainboard. Which chips are responsible for picture of lcd on switch lite?

Hi. On the video connector, counting only the larger pins and from right to left, make sure you have around -5.4V (pin 8) and 5.4V (pin 10.)

Hi there, I am very sorry to answer so late, as I really did not notice that someone has answered to my question.
I am not 100% sure which pins you mean, but I will add a picture with all the voltages I measured on the shown pins.