Is it possible to fix the backlight without replacing the screen?

My girlfriends 5X finally bootlooped yesterday. It just died in her arms, not even bIinking with the notifcation light when trying to power it on. started googling, and found a few tutorials of how to resolder the SOC etc. This is my second time going into a phone, first time was a successfull screen swap of a Huawei P9.

After cooking the motherboard and letting it cool down, I installed it into the phone. It seemed like a success at first, showing the google logo and almost booting into the homescreen.

But suddenly, the screen went black. And it is still black.

I took it apart, waited a while and cooked it again, a few minutes longer this time. Reassembled it, tried to start it, still no screen.

I did notice that the screen was working though, it took pictures, played sounds and reacted to touch. I shined a flashlight on the screen, an d saw that I could see the content faintly, so the backlight wasnt working.

TLDR: Is it possible to fix a non-working backlight without replacing the whole display? The display was already shattered a bit, but we had no issues with backlight beflore. Since it already bootlooped once, I dont think its worth buying a replacement screen in case it just bootloops again.