I had some plugs that I discovered I could flash custom firmware to. It taught me a few skills that I’m still a novice in level in, but I understand much more than when I started with.

I started out with Tasmota and eventually moved over to ESPHome. I’ve taken quite a few products out of the cloud over the years with it including some for friends.

Those devices, plus HomeKits as well as Zigbee as you mentioned are all great and all a central part in my Home Automation.