Hi, I’m Nicole, I’ll be happy to help you out today.
I will try my best to assist you with this so that you find a satisfactory solution.
It seems this is a hardware problem as per all the tests you have done.
But just to be sure, open device manager by right-clicking the Windows logo then click device manager.
Double-click Keyboards on device manager.
Next, right-click HID keyboard device then click uninstall device. Do it on all the entries you see there ( if you see multiple entries ).
After that, restart the system and then test the keyboard after the restart. If the issue will still persist, I suggest having your laptop keyboard checked at a repair shop.
Thank you.