Hello there,
Could you please send us a picture of SN code at the bottom of machine?
You can try to clear CMOS first: Please unplug the power supply and HDMI cable. Then press the pinhole of “CLR CMOS” with a pin for about 10 seconds. Ten minutes later, plug the power supply and HDMI cable, turn on the PC again.
Please wait about one or two minutes, if you can go to the system, Please repeatedly press delete key as soon as your restart the PC, go to BIOS. Go to Boot option, enable fast boot, press F4 to save.
Here is a video tutorial: https://mega.nz/file/2nIRGaYI#M2aIM2bkOJshrhE8sK8MNiKopfyHlqyjnn86TypZp2w
Could you please send us the link of the external graphics card you linked?
Then we can help you better.
Have a nice day!