Try setting the wrap_on property of the Column Panels to never. This will prevent the effect you’re getting that makes all the colums end up below each other:
(You don’t need to change the wrap_on property of the Card Column Panel, just the ones on the inside)
Here’s what that looks like in an emulated iPhone 5:
Here’s that example app to clone:
https://anvil.works/ide#clone:2H74LGJEJ7BRP6I4=ETMZJQEGB5UVM4RME5CTNR2P