It is the UI. To operate any Z-wave plus devices you will need UI6 or higher.
I know from experience as I have a stable system on UI5. ZW+ devices will not configure on UI5 or lower.
You have stated you have UI2, Z wave plus devices will not work on UI2 or UI5.
I don't have a solution for you, other than move to UI7 ( and a new controller).
I wouldn't like to be in your boots right now, moving 60+ Devices might be problematical, mostly due to incompatibility with older devices.
A simpler solution might be to move to another automation system as I have decided to do.
Good luck.