Replying to my own post. I think this forum post below from “Loki” provides the answer to half my question. tldr; the “Detect Motion” and related features will invoke the 12 sec cloud.
But I still haven’t figured out how Wyze so smoothly is able to pierce my home firewall. Don’t get me wrong I am super happy with the app and hardware. I’m just thinking about all the trouble I had to go through back in the day to get my old BlueIris based system available externally. I had hours of messing with my router. And for Wyze it’s just …ding…and it works. Fantastic, but how?!
The 12 second event clips (stored in the cloud) are independent from SD card recording (in either event only or continuous mode).
If you turn off Detects Motion and Detects Sound in Event Recording and turn off Smoke Alarm and CO Alarm in Alarms Settings, then you will have no video sent to the cloud.
The above does not prevent you from using the Record Events Only mode for SD card recording found under Advanced Settings > Local Storage. In this case, the motion detected video will only be stored locally on the SD card. Every one-minute segment from mm:00 to mm:59 that contains any detected motion will be retained on the card, other 1 minute segments will be discarded.