There are two comments/questions here and I'll try to address them one by one.

Secluso vs. Frigate: I think you correctly mentioned some of the differences. We intend Secluso to be replacement for Ring-like WiFi cameras. Therefore, it needs to be easy to set up and use and provide similar functions to a Ring camera: the user plugs in the camera, opens the app, scan a QR code and perform a pairing process, and the camera is ready to use with its strong end-to-end encryption. The self-hosted version of Secluso requires a few more steps, but we've tried to automate it as much as possible. Home Assistant and Frigate are great platforms that are capable of providing good privacy (although they don't support advanced end-to-end encryption that Secluso does with forward secrecy and post-compromise security through MLS), but they require several steps, e.g., prepare/configure the IP camera, install and configure Frigate, integrate Frigate with Home Assistant, and configure remote viewing via cloud relay or VPN. Also, they are typically used with wired (Ethernet) IP cameras. WiFi IP cameras are possible but the RTSP stream between the camera and hub will be unencrypted, which might be vulnerable to eavesdropping.

Need for cloud relay: We have considered STUN and we are planning to deploy MLS over WebRTC for livestreaming (using the DAVE protocol) to improve the livestream performance. But this doesn't completely eliminate the need for a relay. If a STUN connection cannot be made due to some restrictions in one of the networks (that the camera and app are connected to), we will need to fall back to the relay. Also, if the phone is off/disconnected when an event video is recorded, we would like to transfer it (encrypted) to the relay ASAP in case something happens to the camera (e.g., it's taken by the intruder).