I know that there exists projects such as https://github.com/OpenIPC and https://github.com/themactep/thingino-firmware. These allow you to replace the firmware running on some of the Chinese IP cameras with an open-source alternative.

Our project specifically is only meant for Raspberry Pi Zero 2W. We decided on this early on due to Raspberry Pi being a safer source for hardware, and it allows much more customization (e.g. custom 3D printed cases, our HAT, etc). We also wanted it to be a WiFi camera that's super easy to setup and doesn't require technical knowledge to use.