So I am definitely not an electrician by any means but I noticed on their site the ZEN05 says “Do not install the device in a place with direct sun exposure, high temperature, or humidity.” which seems pretty silly to me for something that two lines above says it is outdoor rated hah. I bet that is why they said not to use it though, heat+melting ice will generate humidity or something. I wouldn’t be placing the device next to the heating pad if it was me anyway so I would think it would work, your logic seems sound to me, I probably wouldn’t even have asked zooz now that I think about it.

That said, I’m going to need to hear more about these heating mats, I have some sidewalks that I don’t enjoy shoveling hah.

ETA: forgot to include, I use the GE version of that ZEN05 outside (since 2019) plugged into a GFCI outlet and it works fine, it definitely has very direct sun and gets all weather too.