Laptop repair question

Hey just asking what could the problem be with my Legion 5 pro laptop i sent it to the service center because there is no display both on the built-in and external monitor. They took it and said that even after removing the storage nvme the device still wont display on either built-in or external displays, thus they concluded it cannot be repaired. but it still powers on the fans revv and the keyboard lights work. what to do?

The problem is with the laptops GPU not the storage. The GPU is the sole component that delivers the display to the laptop screen and the external HDMI/VGA. You could get it working again by reflowing the GPU, but it’s not a permanent fix. The reflow can last a day, a week, a month? The last laptop I reflowed lasted 2 years but that’s because I put 2 thick thermal pads under the heat sink before screwing it tightly down. So there was constant pressure on it.
You can use a heat gun to reflow the chip or even a hair dryer, but the downside is you’ll need to remove the motherboard completely and you’ll need to make sure you don’t heat up any other delicate components near and around the chip. The only way to permanently fix it would be to remove the chip and resolder it completely. But you’d need expert equipment for that. Again if you attempt a reflow it won’t fix it. It’ll just be a temp repair.