I’ve just built my first NAS. I went very overkill for my needs, so bought 5x8TB drives, 32GB of RAM, a Ryzen 5600G, and 1TB of NVMe SSD storage to compliment my HDD space. I’ve installed TrueNAS and have plugged the HDDs into a RAID-Z2 config, yielding about 20TB of usable space, with the 1TB SSD being a separate pool for anything that can benefit from faster IO, which have generally been applications / VMs. Currently using it as a network drive for all my data, and am using BorgBackup to ensure everything’s backed up. At some point I’d like to get a remote BorgBackup repository going, but I’ve not gotten around to it yet.
I’m also using it to host a VM for my web dev projects I can access via RDP and Tailscale, and have started installing PhotoPrism for my photos, SyncThing for my dev projects (so I can continue coding across my PC and laptop seamlessly), and eventually I’d like to get Plex / Jellyfin going, though I already have a setup going via WhatBox.