Laptop display error or where does that come from?

It is everywhere and always like that. Also in the BIOS. There's no problem on an external monitor. Is it enough if you swap the screen?

I once worked for a large company in technical customer support and had exactly such issues.

The screen error looks a bit unusual, or I have something similar not yet seen.

You have excluded with the external monitor and the biostest, that it is a system error and the hardwaredefekt already well limited. It could therefore only be on the display, display cable or display port / port on the mainboard.

You could test the cable by making the display a little bit open and see if something changes in the picture. If so, it is likely a cable break or loose contact, which often happens, as the display cable in many laptops duch the hinges and it is daduch friction and belatung exposed. Therefore, we have always ordered the display technician to supply the display with security during display repairs.

The port on the motherboard is rarely broken.

otherwise it is the screen and an exchange would fix the problem. Inform yourself well in advance if you want to repair it yourself, because some models are very difficult to get to the display ran.