Specifically, using dash cast (included with Cast or share camera stream · AlexxIT/WebRTC Wiki · GitHub) to push a RTSP or camera stream, it goes up to a minute in lag. Whereas with just viewing it on the dashboard it’s near instant.
This is with a eufy, happy to try a different cam but worried about the same result. It might very well be the chromecast, but unfortunately v3 doesn’t seem to support dash cast :-(. Haven’t tried v2 yet.