Thanks! I've updated the link. I always just use Batocera or something like that, which has Emulationstation and Kodi set up for me. So I don't pay a lot of attention to the included projects and their development state...

I didn't include this, since OP wasn't mentioning retro-gaming. But Batocera, Recalbox, Lakka, RetroPie are quite nice. I picked one which includes both Kodi and Emulationstation and I can switch between the interfaces with the gamecontroller. I get all the TV and streaming stuff in Kodi, and Emulationstaation launches the games. And I believe it can do Flatpaks and other applications as well.