1. all cameras (firmware v4.36.9.139) have 64gb+ micro SD cards and record to local storage -- many people seem to have issues with anything greater than 32gb in v3's but I've found that this Verbatim tool [0] formats FAT32 at high capacity with no problems
2. all cameras have wz_mini_hacks [1] on the SD card with RTSP enabled
3. all cameras are connected via ethernet instead of wifi using this adapter [2] and wz_mini_hacks config
4. network blocks all outgoing internet connections for all cameras to keep them LAN-only -- this means I have to connect to VPN to review video when outside the house, but I'm cool with that
5. all RTSP streams are also recorded over the network via Agent DVR [3] to a NAS
6. the Wyze app (free tier, not paid) works normally with all of the above in place -- I find it much more intuitive to review recent videos in-app (streamed off the SD card), and then review the very occasional older video from a computer off the NAS (scrubbing through in VLC on a computer)
For what it's worth, I don't use them like a Ring camera where you're responding to realtime video events / talking through the camera to a delivery person -- this is mostly just for 24/7 recording. I have all object/motion detection events turned off, just a straight uninterrupted feed recording local and on the network.
Links:
0. https://www.verbatim.com/index/search.php?words=fat32+tool
1. https://github.com/gtxaspec/wz_mini_hacks