@WayneY Look at your RPO codes -- is there a G65? If there is, that's what shows that the rear OE shocks were manual self-leveling Nivomats. The ZW7 by itself does not. (From what I've seen here not all ZW7 Premium Smooth Ride SUVs of your year had them.)
Your severe bounce on the front could be caused by not having the front jounce stops contacting the lower control arms at ride height. Check to see their condition. That contact is a fulcrum point in the front suspension.
Here's a picture of a jounce stop NOT contacting the lower control arm, which is NOT what your suspension needs to work correctly.
View attachment 438734
There were a couple of members with used Nivomats for sale; if you're interested reply to this post and we'll find them for you.