But is Blue Iris really worth dealing with Windows over? I think Frigate has pretty much caught up by now and is developing quickly.

Yeah webrtc is one of the best in this regard. Unfortunately I can’t display 4 of them on my kiosk tablet.

I don’t think you can do much past just display the live (usually somewhat delayed) camera feeds. If you have some external object detection, you could probably feed the detection events to Frigate. That would make it as efficient as anything you could do natively in HA.