I recently purchased a house with a rachio sprinkler system and I don’t know which model it is and I don’t see it connected to my WiFi but I have seen it running but it’s not getting enough water on the front lawn.
Gen 2. Gen 1 looks square. All handles 2.4GHz. The Gen 3 also does 5GHz. So, if your WIFI is only 5GHz, that might be why. If you have not done it yet (I would guess you may have), you will have to connect through the app in order to put in the credentials for your WIFI.
Video showing 2 & 3: https://www.youtube.com/watch?v=nxaqlt6eMm4
Here are pictures of all three: https://justclickappliances.com/rachio-gen-1-vs-gen-2-vs-gen-3-vs-3e/