I run CoreELEC/LibreELEC on all my streaming devices. It only runs Kodi but since Kodi has tons of addons it is fairly easy to customize. Kodi also plays pretty much any codec in existence and has support for various remotes.
If you’re planning to play 4k content you will want something with a little bit more power than a Raspberry Pi 4. For Dolby Vision you need one of the few supported devices.