Only one main IQ Panel 4 can be part of a system. You cannot pair two IQ Panel 4s together.
You would instead want an IQ Remote, available here. The IQ Panel 4 can be moved to an area better suited for signaling and the IQ Remote placed where the IQ Panel 4 is now.
The IQ Remote mirrors the UI of the IQ Panel 4, and cameras can be viewed on it, but it does not act as a Z-wave device/repeater.
Z-wave is a mesh network. It is extended and improved by adding repeating z-wave nodes. Suggestions on how to improve signaling can be found in the guide below!
Some Z-wave devices will require that you bring the main panel close to the device or for battery devices like locks, bring the lock close to the panel, and pair it within close proximity. Always perform a rediscovery after done adding new devices.