It looks like if I exclude those three values it makes the VM. So maybe the better question is; if I'm taking these values from the template, am I not meant to override them? The description seems like an odd one to not be able to override if that's how it works.

@AtaxyaNetwork It is Debian 12. I found the problem and will post again if there's more issue. The VM stopped using its static IP, not sure how that happened, but I re-added it to /etc/network/interfaces and it's working again.

Dual stack support for IPv4 + IPv6 on the management interface in XCP-ng 8.3: requires reinstalling to define both IPv4 and IPv6 for the management interface is still experimental, there are a few known issues CC @BenjiReis @gthvn1 @andriy.sultanov