I had from now on the same black line on the screen. In the BIOS, the stroke is there and if I change the resolution is still there on the same place. What can I do about it?
Defective GPU or Monitor.
Since software is excluded in the BIOS.
Simply connect monitor to another device and follow OBS.
It is clearly a damage to the monitor, more accurately on the connection from the driver board to the display panel. You should complain that and take the warranty as it is a material defect.
Try another port on your graphics card.
You can also try to boot with your internal graphics unit of your CPU. (Either set in BIOS or remove graphics card)
If the error is there too, you'll probably have a defective monitor.
If there NI therethen, then your graphics card is broken.
Monitor hardware damage irreparable.