I wanted to chime in and say I have had no issues with my ZigBee or Z-Wave networks (I run both) not being reliable in my house. I made sure I built out the mesh by installing devices close to my server closet where my ZigBee/Z-Wave receiver is and then out from there starting with powered devices that work as repeaters.
Some smart switches can also be configured to run in Smart Bulb mode, where they can be used to control a smart bulb without actually shutting off the power. You can also set up device groups to be able to control the device directly even if Home Assistant is down. I find that this gives me the best of both worlds, as I can do cool things like changing light color and intensity with automations while still having the ability to turn the light on/off if my server or WiFi network goes down.
A standard smart meter can't exactly. It only measures the energy that is getting consumed into the house or whatever is behind it. But some companies have started to develop energy profiles on appliances though. Say for instance that your washing machine pulls a specific amount of power for 5 minutes, then a different amount for 15 minutes, etc as it runs through the various parts of the cycle. It creates sort of an energy signature that they might be able to tell what it is even if they are only looking at the combined usage of everything in the house. In my experience, this kind if profiling isn't very accurate, but it might get better over time with AI models.