Why do I get a dim screen on a Razer Blade 15 laptop if I enable the dedicated GPU?

Context : I bought a Razer Blade 15 from 2022 RZ09-0421 laptop second-hand, it was slightly dirty and some of the keys as well as the touchpad weren't functioning properly. I opened it and cleaned everything, which implies removing the motherboard to gain access to the keyboard. I disconnected a bunch of different ribbon cables, also changed the thermal paste while I was at it. When I put it all back together and booted, the screen was so dim that it was unreadable. I asked for help to an AI at first, but was not convinced by its answer: It suggests that I may have damaged the ribbon cable in

Question by Alexandre Leonardi on Super User, licensed CC BY-SA. We show a short excerpt and link to the original thread as credit.