So upon some more research, I found a few places that said that the cirrus link module does not publish to the MQTT broker upon tag value change when a custom namespace is used. The zwave devices don't appear to be Sparkplug compatible.
That being said, it also appears that there is a topic below the targetValue topic named "set". So using the Cirrus Link publish script to publish to that topic, I am able to control the device through Ignition with a script expression attached to the button.
deon.korb, I will look into the bug you referenced, I had not seen that "make created tags writable" under the custom namespace configuration. That did "allow" me to edit tags, but since apparently the topic of /set below the target value is what needs the payload of true or false to change state of the device, the setting of making tags writable makes no difference. Perhaps this will become relevant with other zwave devices in the future.
michael.flagler, I did find the software of MQTT Explorer and utilized that to initially publish the payload to /set, it appears to be something that will come in handy!
I am excited though to make this step forward of controlling my device! I suppose I will have to do some learning about what topics a zwave device generally has, and if they are "standardized" to the point that I can develop objects within Ignition that allow me to pass the simple parameter of the device name to it and have it function for what I need.
I have a little experience with scripting such as vb.net and a little python, but looks like I should expand my horizons with python to use in Ignition!
Thanks,
Taylor