I had at my home spare Raspberry Pi 4B in 4GB version. I installed the Android TV version of LineageOS on it and then Jellyfin and SmartTube apps (something like NewPipe, but for TV). I highly recommend it.
Edit: You may also find these apps useful:
LocalSend - to transfer files between devices in the same network
KDE Connect - to control your TV with your phone when you don’t have any Bluetooth keyboard around you