In your position, I'd start with local control - you can do this with your existing devices. They'll still be on wifi, which isn't ideal, but you should get much better response times when your devices are just pinging a controller on your local network instead of a cloud server.
Once you've got local control established, then I'd start looking at gradually upgrading/replacing devices.
I have a Danalock which I got through the Ultion brand. It looks like Ultion now use Nuki for their smart locks, rather than Danalock.
You get an Ultion lock (with optional matching keying if you have multiple doors and want to use the same key for them), with an included Danalock/Nuki and - importantly - if you get it fitted by a qualified locksmith, it meets the BS3621 standard so it won't invalidate your home insurance.
Valetudo still requires wifi, it just doesn't require an internet connection.
Without wifi you'd need something with physical start/stop buttons on the robot, or with a separate remote control - not sure if anything like that exists (many robots have buttons on them but usually only very basic controls, nothing for schedule cleaning etc)
I bet you could run a massive wyoming model on that, for super speedy voice control through HA
This sounds cool! It definitely sounds like something you could build off an RPi or Arduino. You might find some inspiration in the Home Assistant forum, they've got a section for showing off cool projects and I'm sure I've seen this type of thing in there before.
If you can figure out which zwave parameter controls the limits (which you can often find by reading the manual or tech spec of the device, or by checking your zwave logs after refreshing the device's values or reinterviewing it), it should be possible to set that parameter directly, depending on your setup. I use zwave2mqtt via zwaveJS UI, so I would either use the MQTT Publish service in HA to send the command to update the parameter, or use MQTTBox (or whatever has replaced it now it's no longer supported); but I'm not sure how you'd do it with a different zwave setup.
That's bizarre. The electrician probably tried this, but have you measured the power draw of the smart switch? Maybe if the circuit was already on the brink of being overloaded, the switch is pushing it over?
You just need to look through each stage of the process to identify where it's failed. The HA part is easy, just check the trace for your automation to make sure that the command was successfully passed to google mini; I don't know how to access logs etc for the google part of the process.
Also, if it's a tuya device, is there a specific reason why you're controlling it via google then tuya cloud, rather than directly through one of the HA tuya integrations? You'd have fewer points of failure that way.
Maybe a couple of times a year there's a problem with my HA + (mostly) zwave setup, but it's usually something I can ignore until a convenient time. I've had a problem that needed fixing straight away maybe twice in four years.
If you have any wifi devices though, oh my god, don't change your password. Apparently "just factory reset it!" is the standard way for smart device manufacturers to handle wifi network changes. How do you factory reset it? "Press this tiny button sixty times until it finally reconnects and then redo all your configuration changes". Nightmare.
Hmm. There are lots of smart plugs available, and lots of options in terms of hubs etc depending on how much fine grain control you want and whether you want to be able to add more different types of devices in the future. But my question would be, what's to stop the kids just unplugging the smart plug and plugging the tv straight back into the wall? It's what I would have done!