

Separate the use-case here:
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For your desktop, whatever works. There is no one distro that gives you some leg-up on performance or anything else. You can install the same software on all, and the kernel is largely the same.
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Just get or build a NAS for hosting media. A Synology or Qnap has a bit of added cost, but the maintenance overhead is reduced by a LOT versus running TrueNAS, OMV, or similar. That being said, choose the right tool for the job, and don’t just run Debian for this purpose because it just adding admin overhead you don’t need. This probably has been solved from your specific angle. What you want is simplicity in maintenance. Being able to hotswap and repair a failed drive means a huge win.






You literally say in your post you’re building another machine.
Make it a single purpose machine that does the thing you need it for.