Blank MacBook display after wake from sleep

my macbook started having display problem yesterday after i tried to awake the laptop from sleep state. It only shows blank screen, and no image, but the backlight display is on. The whole laptop still run as if it was fine, even the brightness setting is maxed out. I tried connecting it to another external monitor and it shows all the mirror display. Tried all the NVRAM and SMC reset, reinstall my MacOS, also done disc utility checking but no error results and it still didn’t fixed my blank screen.

Is there any solution for this? My macbook runs on MacOS Catalina and haven’t upgraded it to BigSur. I went to my local Apple service shop, they said that it’s because of the LCD went wrong but I’m still not sure.