For those looking for a bump in difficulty above Hard Mode, without overly increasing the complexity, I offer you the following:
Whenever the app would deploy a regular (grey) deployment group, replace it with an elite (red) deployment group. Follow that group's instructions as normal, but use any upgraded abilities when applicable (for example, if replacing Jet Troopers with the elite version, treat the surge: +1 damage listed in the app as surge: +2 damage, and add an additional blue die when attacking a target within 2 spaces).
Whenever the app would deploy an elite non-unique deployment group, place a strain token on that card. Apply additional Health to figures with a strain token on their deployment card equal to half that figure's total Health, rounded down.
I was able to win the first 3 missions of Jabbas Realm with this rule, but only just barely, which was a great feeling.