Help with my build spec (Node 804, 10Gbe)

I have long been a QNAP user. I have a QNAP 470 Pro that is getting old and slowish. I should replace it, but I am not loving the QNAP model range at the moment. I am thinking to build my own.

My use case: I’m an ex-IT geek. I am comfortable to build my own, but this is something I really don’t do much anymore. I want to buy something that I can build and forget. It will sit on my desk – so I want it to look presentable – but after building this and the OS, I really don’t want to dabble again for as long as possible.

This will serve primarily two functions. First is as a home NAS. I will only access over SMB; no streaming required. Second is as a download station (think Sabnzbd, Sonarr, Watcher, etc.) Occasionally I may dabble in other things, but I really haven’t done that in years.

Thoughts on what I am after (but open to suggestions):
Case: Node 804. This will sit on my desk; want something sleek but flexible to my needs.
Motherboard: SuperMicro ATX (only because these seem to be often recommended). See requirements below.
CPU: I’m thinking an i5/i7. I won’t be doing anything intense, but would like something that will last for several years.
Networking: I would like something that supports dual 10Gbe. I’m not running 10Gbe at home yet, but will probably upgrade in the next year or so.
Drives: I currently have 4x WD 12TB Gold drives from my QNAP that I will repurpose. I also backup to an external drive (using 2x 14TB WD drives)
OS: I am open here. I hear Unraid talked about; TrueNAS Core could also be an option I suppose? I just want what’s easy and has a well-supported community plugin environment.
Caching: I would like to add an M2 disk as a read and/or write cache.

Questions:

  1. Would the above work? Is there anything obvious I am missing?
  2. What software would you go with – Unraid? TrueNAS? Something else?