I’m still learning, so take this with a grain of salt. But here’s what I think.
An upright bike will balance itself on its own, a Cruzbike will balance itself through your pedaling motion. Get more quiet miles in, try to relax your grip on the bars and you’ll find the small steering direction changes that occur when you put pressure down on the pedal is exactly what’s needed to keep the bike upright.
And when going down fast descents, put pressure on both feet, pressing yourself into the seat. That stabilizes steering significantly.