I switched from an I3-530, nominal TDP 73W, to an N-100, nominal TDP 7W, and power from the wall didn’t change at all. Even the i3 ran around 0.1 CPU load, except when transcoding, and I’m left with the impression that most of the power goes into HDDs, RAM, maybe fans, and PS losses. My sense is that the best way to decrease homelab power use is to minimize the number of devices. Start with your seyrver at 60W, add a WAP at 10-15W, maybe a switch at 10-15W… Not because of the CPUs, necessarily, but because every CPU every CPU comes with systems to keep the CPU going, keep the power regulated, etc.
I’ve watched enough Lock Picking Lawyer never to want a consumer ‘smart lock.’ Half of them can be opened with a magnet. Maybe commercial grade is better, but I’ve been locked out of my job after every power failure for the last 10 years, until someone comes along with a physical key.
Re homeassistant on a Pi: homeassistant does a lot of database transactions, so you may want to have db storage on something other than an SD card.