Built-in display has backlight but no picture

I mainly use my MacBook as a desktop, so I keep it closed and connected to external monitor, keyboard, trackpad, and speakers most of the time. There was no damage done to it — it’s mostly at the same spot on my desk, I don’t even touch it usually, and it did work perfectly fine the previous time I used the built-in display around a month ago.

What I tried so far that didn’t help:

• Opening it up and removing any dust
• Disconnecting the battery in the process, which most likely caused the SMC to reset
• Opening it once again, disconnecting and reconnecting the LVDS cable to the logic board. The contacts on the connector looked pristine.

Turning it on with no monitor connected lights up the entire display with the center part then fading to black. Opening the lid while it’s already on results in a black display. The backlight works fine since the apple on the back glows. The built-in display does show up in system information.

If that matters, I had the battery replaced in December because the original one had swollen to the point of it being unable to lay flat and the trackpad also became very stiff to click.

As far as other parts of it go, it still works fine as an oversized Mac Mini. In fact, I’m using it to write this question.

What else could I try to fix it?

Edit: I also tried disconnecting and reconnecting the cable in the lid, that didn’t help either.