See your separate thread
Inside a container? Yes, that’s expected. The container is just a subdirectory of the host’s filesystem, so the whole space is available if required (unless you set a quota, which is only supported in certain drivers).
$ incus launch -s zfs images:ubuntu/24.04/cloud test
$ incus exec test -- df -h /
Filesystem Size Used Avail Use% Mounted on
zfs0/lxd/containers/test 133G 323M 132G 1% /
$ incus config device set test root size=10GiB
$ incus exec test -- df -h /
Filesystem Size Used Avail Use% Mounted on
zfs0/lxd/containers/test 11G 323M 10G 4% /