I am using the same Mini as a media server, but I use an old 500gb USB3 SSD as a boot drive and a 4tb USB3 SSD as as media drive. I'm running Mojave with iTunes and family sharing. Also use regular file sharing for copying files and screen sharing to access from another mac.
This works really well for me, I have about a 2tb iTunes library with around 1200 videos and thousands of songs. I access it with two Apple TV's, another Mac, an iPad and iPhone. True, Mojave is no longer supported and iTunes has been discontinued, but it all still works.
BTW, regarding playlists, shared video playlists work fine on the Mini itself and my two AppleTV's. But shared playlists don't work with the TV app on my other Mac. It shows the playlist, but it appears to be empty. And iOS has never supported shared video playlists, so they don't even show on my iPhone or iPad. Shared music playlists work properly across all devices however.