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
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!