It sounds like you've got a solid plan to reset your HVAC system remotely using a smart plug! The high attic temperature is definitely a key concern here. Most consumer-grade smart plugs aren't designed for environments as hot as 135°F, but there are a few industrial-grade or higher temperature-rated options you could consider.
Unfortunately, Wyze and Lutron don't currently offer smart plugs that can handle that kind of heat. However, here are some options that might work for your situation:
Kasa Smart Wi-Fi Plug by TP-Link – This plug is reliable and WiFi-based, but it’s only rated for temperatures up to around 104°F. You could possibly mitigate the heat with some insulation or a vented enclosure.
Insteon On/Off Outlet – While this requires the Insteon hub, it’s designed to withstand higher temperatures, and it's one of the more durable options available.
Meross Smart Plug – Meross plugs are Wi-Fi based and may be more temperature-resistant compared to regular smart plugs. However, you'd need to check specific temperature limits.
If none of these options work in the attic due to heat, you could consider placing the smart plug in a cooler area outside the attic, connected to a switch that controls the HVAC unit.
Lastly, make sure the plug you choose can handle 15 amps and ensure that the installation adheres to local electrical codes for safety.