I run a 5 node kubernetes cluster as my homelab. It has both public and private DNS for local upload (faster) and for remote access and sharing (via a Cloudflare tunnel).

> I don't know how the app will behave when it can't reach the server half the time

Immich has automatic URL switching, so it detects which network it's on and select between the internal and external URLs. When I'm not on my home WiFi it switches to the Tailscale URL. Tailscale must be connected for this to work obviously.