I am running fedora workstation 38 on my laptop which is connected to an external monitor via HDMI. I usually keep the laptop’s lid closed and thus have disabled its display from the settings and use only my external monitor. Whenever I lose power on my external monitor, I open the lid of my laptop but the screen doesn’t turn on until I disconnect the HDMI cable. How can I achieve this without the need to disconnect the cable?
I am not sure you can. As long as the internal screen is disabled and the system knows the external monitor is attached it will try to use the external monitor. Only when the external monitor is detached (hdmi cable disconnected) does it sense the trigger to switch to the internal monitor again.
I think you can do Super+P to switch display layouts.
Please check if your laptops function keys are working or not.
Normally there is a function key to controls displays - internal only, external only, etc.
Switch to Internal Only should wake up the internal display.