I apologize if I am a bit naive I am fairly new to Linux Server Administration and LXD containers. We have a Ubuntu 20.04 host with LXD version 5.20 where we installed distrobuilder using snap
$ sudo distrobuilder build-incus almalinux.yaml -o image.architecture=x86_64 -o image.release=8
...
+ systemctl enable network
network.service is not a native service, redirecting to systemd-sysv-install.
Executing: /usr/lib/systemd/systemd-sysv-install enable network
...
$
The notable difference is that I used the action build-incus instead.
Can you try with build-incus to make sure that at least it works in that way on your specific system?