It’s a media center, you can play your local files or you can use add-ons like the official jellyfin addon and connect to any jellyfin server.

If you’re comparing the official jellyfin client apps to kodi, then kodi looks much nicer with more features but requires better hardware. It should work on on your Mac fine but depending on what android tv specs you have it may be a bit slower than the jellyfin client.

Kodi doesn’t have a server feature like plex does where you can serve media to other devices. A more direct alternative would be jellyfin, which even works well with kodi as the media player.