Not open-source/audited, but Apple HomeKit Secure Video is light years ahead. Encrypted in-house on your own hardware (ATV or HomePod), they don't have the keys, excellent UX, hosted service, super easy to use. I'm all about the self host, but assuming Apple isn't straight up lying, they have build something that's too good and too easy. I buy cheapish HKSV cameras, and block them from accessing the WAN, so there's minimal Apple tax outside one hub.