I guess it could be the distant from it. I have a ton of Zwave devices in my network because they are just so much more universal if i ever want to go away from ST, and I have several GE remotes I use as secondary controllers when ST is sucking and being slow.
I would try and remote it and repair it with the hub. My dimmer is about 10 feet from my hub, but i don’t see why it would be so flaky if it was so far away. Did you try getting a Zwave Jasco Wall outlet and plug it in between, i believe those act as repeaters.
Yes Brad, the whites are the neutrals. Some new switches come with a white lead about 4 inches long (pigtail) where you untwist the bundled white, add the pigtail and then connect the other end to the switch. Line and load are the same as the old switch
Be sure power is off before you open the wall up
Rick