I'm a bit confused on the Homekit Secure Video/iCloud storage plan side of things.
According to this page at Apple you can view live and save clips without any iCloud plan, but to save video you need the 200GB plan for one camera or 2TB plan for up to 5 cameras.
In Home on iPhone, set up and use security cameras.
support.apple.com
So what clips are you able to save, and for how long? I was thinking maybe it stored the clips with motion for free for 10 days, but the iCloud plans got you full 24/7 recording for 10 days. But, looking at some of the posts above it sounds like even with an iCloud plan you never get 24/7 recording.
We are considering one of these for my mother-in-law for Christmas, but need to plan on paying for the iCloud plan too if it is going to be required to get anything other than live video streaming.