I don’t know how far you are trying to move your devices away from the controller but do consider what is between your device and controller. The number of walls, type of construction, and other obstructions as well as the distance, can severely limit how well Z-Wave communicates. Think “line of sight” at the installed height of the devices and then think about what is between them. Z-Wave is a low power radio signal that is easily blocked or absorbed by dense construction materials. More devices help with difficult communication situations.
I don’t know whether these devices are Z-Wave or Z-Wave Plus devices. Z-Wave Plus devices can communicate at longer distances, support Network Wide Inclusion (no need to be close to the hub) and are better at self-healing.
As a way to better visualize how your network is communicating you might want to look at Graph your Z-Wave mesh (Python, auto-update)