Launches OBS, starts the virtual camera, and then minimizes the window.

obs_virtual_camera.applescript

on run {input, parameters}  -- remove this line if running in Script Editor and not with Automator
	tell application "OBS" to activate
	tell application "System Events"
		tell process "OBS"
			set frontmost to true
			if name of every menu item of menu "Tools" of menu bar 1 contains "Start Virtual Camera" then
				click menu item "Start Virtual Camera" of menu "Tools" of menu bar 1
			end if
			click (first button of window 1 whose role description is "minimize button")
		end tell
	end tell
end run  -- remove this line if running in Script Editor and not with Automator

^ Using this method locked the Option key on my Mac -- required the virtual keyboard to get unstuck

Try this method instead: https://stackoverflow.com/questions/3690167/how-can-one-invoke-a-keyboard-shortcut-from-within-an-applescript