I have an HP-Probook-450-G6 with an intel core i7 8th gen processor and nvidia mx130 graphics card.I'm using Ubuntu 20.04.3. I originally had the noevoue(I'm sure spelling is wrong there) driver running. I plugged in a vizio monitor through HDMI. Ubuntu recognizes both built in monitor and external monitor. However, it only shows things on the external monitor no matter how I set things up on the display settings. I've set the built in monitor as the primary monitor, dragged the monitors to the position they should be, hit apply and restarted. Every single time I restart, even if I unplug the external monitor, the laptop monitor shuts off and I'm left having to reconnect the external monitor and join the screens so that I can at least see things on the external monitor. The laptop monitor only works on initial boot when I select ubuntu from grub, then it shuts off and switches to external monitor. I have tried installing the nvidia 470 driver to see if switching from default to recommended driver helps but it had no effect.
Note: I am dual booting windows 10 and both the laptop and external monitor work just fine together. I set the external as extended from the laptop and it works flawlessly even after reboot. Therefore I know that the issue is OS specific and not something to do with my hardware.
