Advice for a full DIY NAS for newbie

[Enquiries]

Hello, I need your expert advice for a full DIY NAS parts list available in the Spanish market (EU).
The Goal: A robust 24/7 server for mixed Business and Home use (media/Plex).
My Strict Requirements:
Connectivity: I require a 10GbE NIC (Single port is fine).
Remote Access: I am behind ISP CGNAT, so I will rely exclusively on Cloudflare Zero Trust tunnels (no port forwarding/DDNS required).
Data Integrity: The build must support ECC Memory. This is non-negotiable for my business data.
Could you recommend a Motherboard/CPU/RAM combination that supports ECC and 10GbE natively (or via PCIe) that is easy to source in Europe?

[ed]

For the motherboard and CPU combination, the safest option in the EU market right now is an AM5 board with ECC support paired with a Ryzen processor that accepts unbuffered ECC memory. A good match would be an ASUS Pro WS B650M ACE or the ASRock Rack B650D4U. Both support ECC, have a solid power design, and work well with Ryzen 5 or Ryzen 7 processors for Plex and business file handling. The Ryzen 5 7600 is normally the best balance of power and efficiency. You can add two sticks of 16GB ECC DDR5 which gives you 32GB total and keeps the system stable for both ZFS and business workloads.

For 10G networking a simple PCIe adapter such as the ASUS XG C100C or a Marvell based card will slot straight into these boards. They work well under TrueNAS, Unraid, and Proxmox, and they are widely available in Spain. This avoids the need for a more expensive board with built in 10G.

For the chassis, look at the SilverStone CS381 or the Fractal Design Node 804 combined with an internal drive cage. Both give you the bay count you need and room for future expansion. If you prefer a more traditional tower with space for twelve or more drives, the Fractal Define 7 is often the easiest to source across the EU.

A reliable power supply such as a Seasonic Focus 550 or 650 watt unit will keep the system running quietly and efficiently. With this setup you will have no difficulty running Cloudflare Zero Trust tunnels for remote access without port forwarding, and Plex performance will be more than enough for home use.