Could this same kind of interface have potential for use in the handheld console form factor? The gamepad-like buttons on a handheld are often reminiscent of those on a TV remote control. The handheld generally adds touchscreen control, but this feels like it might be comparatively easy to account for. Of course, ultimately we'd probably want to see something that's sort of halfway between this Bigscreen and Plasma Mobile. Perhaps a new project altogether?
You could probably just try this on a Steam Deck. SteamOS is just a custom atomic spin of Arch, with full KDE already installed (switch to Desktop mode), and the device is a touchscreen. I don't have mine in front of me at the moment, but I imagine Plasma Bigscreen is already in the Arch or AUR repositories.