Basically, I’ve already given up because I haven’t been able to do it for 8 hours. The worst thing, by the way, is vi-Editor.
But now I can’t find a Proxmox helper script either to create a new HAOS-VM.
If you are running NGinX, then your HA service is probably only running HTTP and should be accessible on http://homeassistant.local:8123, which is the direct connection bypassing NGinX.