Look for air mouse. It’s basically a wiimote. Uses gyroscope to pretend to be a pointer device. You’ll need that because you’re basically going to need to use a web browser if you want to go down this path.
It’s not a nice experience but all the nice experiences you won’t like.
All the TVs built in stuff is not going to be the best experience. Doubly for self-hosted. A tv with android os, or a dongle inserted into a tv will do much much much better than samsung or lgs apps. An appletv too but then you’re spending a lot more
Multiply your server wattage by 8 hours. That’s how much battery you need. It’s probably not going to be a cheap investment.
The alternative would be to keep your ups and invest in a generator you can kick on if there is a power cut, but if it’s every day, that might get rough. Technology connections figured out a build it yourself solution a few years ago https://youtu.be/1q4dUt1yK0g?si=8WOTue9-zGghWlxY
in the nicest way possible. lower your expectations. or accept the data-selling, or VPN through europe so you can deny the ads.