I installed the Switch Dock board into a smaller little housing.

Damn! Thanks for letting me know!pretty sure as long as there is an HDMI connection in the dock it will always turn off the screen

Its not a stand. Just a replacement housing. Still the same Nintendo Dock guts inside.normally, the stands on that size comes with a button to disable the HDMI output, and converting it on a USB Hub/Charger only.
not really true the HDMI is just given priorityScreen goes off when it is docked.
not really true the HDMI is just given priority
its the HDMI connection that disables the screen not the switch itself being docked is what I mean it does nothing more than activating a performance profileWell the dock control the output. not like he can plug in a hdmi cable directly to the switch.

been strictly you "can" connect a DP cable directly to the Switch (With USB-C connector) but the HDMI needs a DP to HDMI convertor (there is one on the dock)Well the dock control the output. not like he can plug in a hdmi cable directly to the switch.