You should investigate "mysensors" as well. DIY sensors and actuators; might suit your needs better than Wi-Fi IOT stuff. I've played with it on Arduinos to create temperature sensors and relay actuators for the Pihome heating control system. It was easy to convert from the default wireless network to RS485 wired (just change a few lines in the Mysensors Arduino sketches). Figuring out how to make Pihome understand zone controllers that combine temp sensors and relays is another story.
https://www.mysensors.org/
https://www.pihome.eu/

Thanks.
Sure, I'll check them.

 

A HomeKit user here. It's the most expensive option but I chose it so that I could develop iOS apps to work via HomeKit with compatible switches and my home thermostat. HK has some other advantages and disadvantages. One advantage is that Apple has done a pretty good job of building in a high level of security. I have zero concern about my HK devices being hacked from the outside. I'm sure it's possible but like I said, it's not something I give a second thought to. I also like that any app that controls HK devices, for instance Apple's own "Home" app, can generally be used with other brands of HK equipment. So you have a lot of choice over how you use them.

Thanks.
There are no many things suit for iOS.

 

To secure my home IOT network I use the "Three Dumb Router" approach.

Three Dumb Routers

Thanks.
A great home networking system.