You can set the Default I/O settings for a Flexbox. For example, you might know that you always set up a session as HDMI with an output bit-depth of 10-bit. Instead of doing that every single time in the presenter view, you can set it here once and it will be remembered when you start a new session.
If you are already in a session, make sure you end the session and create a new one for it to pick up the new default values.
If it is a PAYG Flexbox (Weekly/Monthly) instead of a subscription one (CVF Starter, Pro, Glow) then you will be much more limited in the options you can choose to override.