I’ve tried both Unraid and TrueNAS. While I greatly prefer TrueNAS, Unraid is much easier to set up and get going for beginners. It’s been a while since I’ve set up TrueNAS from scratch, but last I tried, it wasn’t a very beginner friendly experience. If you weren’t already familiar with ZFS, you were in for a pretty difficult time.

I’ve never used your exact setup, but I have had issues with a web server behind a WAF not getting the client IP (all user traffic was shown as the WAF IP). In my case, the WAF was appending the client IP in a header, and I just had to tell web app to use that header as the client IP instead of the actual IP. Again, not sure if this helps since I have never used podman or caddy (this setup was with Wordpress and an Azure Application Gateway) but the same principles might apply.

I previously had a QNAP, and they honestly aren’t much better than Synology. I would definitely go the build your own route. For the OS, I really can’t recommend TrueNAS more. I’ve been using it for years and it is rock solid.