Batocera works really well, has a 10ft UI, and includes:
- Kodi to stream local media and can act as an Airplay receiver. I use Jellyfin as a server but I bet Emby would work just as well.
- the ability to run Flatpaks
- a nice 10 ft UI as the default and allows for customization
- emulation backends and moonlight game streaming
- the ability to pair Xbox, PlayStation, or any other Bluetooth controllers
Get a usb IR receiver like FLIRC or something similar with HDMI CEC to control everything via standard remote.