The Hub 2s video output does not produce a mimic of it's screen. I've connected the video out to a stand alone monitor and to a Crestron DM 8x8 video processor. What shows in both instances is what appears to be an extended desktop, that just produces gray. Looked through the settings and see no options related to video output. If I bring up multiple apps on the Hub and move the screen divider around, I can sometimes get the apps to show on the secondary screen but then they don't appear on the Hub.
However, if not, simply plug in a USB keyboard, start a session, and press Win + P to bring up the project settings. Then select duplicate and end the session, and it should stay on that for future use. Full details here.