>Trying to get Windows laptops to keep outputting to an external display with the lid closed has always been a hassle for me
Can't concur with this. My windows laptop is has its lid closed and is outputting to a display. Only thing I do is uncheck the default behavior of putting the laptop to sleep when the lid is closed. This should be enough. Did you do this?
"Clamshell mode" is more than just not going to sleep when lid is closed: it still goes into sleep when you close the lid and have no monitor attached, which also means it goes to sleep if you unplug the monitor and lid is already closed, and out of sleep when lid is closed and you plug a monitor. (TBH I don't know if Windows does that or not)
There may be conditions around having input devices as well, can't recall exactly.
There also used to be a setting to disable wake up from bluetooth devices but it seems to have disappeared. (I was using that setting to prevent a DualShock 4 gamepad - which powers on all too easily - connected via bluetooth to wake the computer)
