

Ah, got it. That plan should be great. You can segment your own wired+WiFi network with that hardware, and even do Wireguard from the hAP ax2 to get whole-network egress via an outside VPN service at a good data rate, if you want.
The other devices you might consider as the router are the GL-iNet Slate series. They will be slower as a VPN router, but they’re pretty small and light. They come with a skinned OpenWRT, but in most cases you can install a build of the unmodified OS if you want.
For DIY consider a setup that supports ECC RAM to help prevent corruption. Any good server motherboard should do.
Unraid is pretty easy to get going on. That’s probably the direction I would take in your situation.
Also, if you’re not doing 3-2-1 backup now might be a good time to consider an off-site backup plan. That 4-bay Synology at a friend’s house with a VPN path would be an option for critical data. You could give them some partitioned space on there and on your new NAS to compensate for the power usage. Setup Borg or Restic and it’ll be encrypted on the remote NAS, and benefit from incremental and dedupe to minimize bandwidth usage.