I hit the keyboard area (right side area of the keyboard. That's where the battery is located under the area) of my laptop by accident and as a result, display glitches show up on the screen.
The issue never shows up in BIOS/Windows 10 safe mode/Ubuntu recovery mode (GUI less terminal screen). I've checked and reseated all the cables that I can find under the back cover. The issue still persists if it's connected to an external monitor. I'm able to use it normally only if windows is in safe mode/Ubuntu in recovery mode.
Unfortunately, my laptop's out of warranty now. I'm still looking for a way to sort it out. If anyone had found a solution to this strange issue, please share it thanks.