There are companies that advertise their products doing everything locally. Eufy for one. Although, be warned that anything that sends you a push notification must send SOMETHING to the cloud. People lost their minds a year or two ago when someone pointed out Eufy’s push notifications send recognized faces to th cloud as part of their push notifications. Eufy did add a warning and the option to disable, or made it opt in I think.

Anyway, the point of all that is it’s all a matter of degrees. Ring and Nest rely heavily on the cloud to process your video and do just about everything. But there are local solutions with varying degrees of local.