Aha! Now it makes complete sense!
On another note, I started to form a hunch that you might want to connect your endpoints in both directions - e.g. from 10.10.6.13 --> proxmox56 AND from proxmox56 --> 10.10.6.13 - mainly based on your initial setup with two services. If that is your goal, there's a clean way to do that without creating a service for each endpoint. Instead you can use a feature that we call addressable terminators, which we have discussed here.
The example in that thread intercepts hostnames in a wildcard domain, and the hostnames map to the identity names. You could just as easily intercept a subnet and name your identities as IP addresses within that subnet. Feel free to start a new thread if you have questions about this so-called addressable terminator technique.