Thank you for contacting Intel Communities.
I am sorry to hear you are having issues with your laptop. You have tried almost all recommendations I could give.
At this point, I would try testing each of the available graphics driver versions available to see if any of them solves the issue:
Downloads for Intel® HD Graphics 620
Check for any BIOS update available.
If the steps above don't fix the issue, I recommend contacting Asus for a possible RMA since this could be related to a defective graphics controller.
Please let me know how it goes.