Unable to get static ipv6 working on LXC

[smittychifi]

My ISP has assigned me a block of ipv6: 2001:19c0:1::1c00/120

I'm currently on Proxmox 7.4.

After setting up a new Ubuntu 22 LXC, I've added network settings like so:

Static IP: 2001:19c0:1::1c03/120
Gateway: 2001:19c0:1::1c01

I've also tried updating the bridge on the node to include an ipv6 address:

Static IP: 2001:19c0:1::1c02/120
Gateway: 2001:19c0:1::1c01

I've also tried updating the RA setting under /etc/systemd/network/eth0.conf like some people have suggested in other threads without any change.

I always get the same result:

ping: google.com: Temporary failure in name resolution

ip a:

1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue state UNKNOWN group default qlen 1000
    link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00
    inet 127.0.0.1/8 scope host lo
       valid_lft forever preferred_lft forever
    inet6 ::1/128 scope host
       valid_lft forever preferred_lft forever
2: eth0@if69: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc noqueue state UP group default qlen 1000
    link/ether 72:43:48:e6:bf:3a brd ff:ff:ff:ff:ff:ff link-netnsid 0
    inet6 2001:19c0:1::1c03/120 scope global
       valid_lft forever preferred_lft forever
    inet6 fe80::7043:48ff:fee6:bf3a/64 scope link
       valid_lft forever preferred_lft forever

and finally my lxc.conf:

arch: amd64
cores: 8
features: nesting=1
hostname: lxc.domain.com
memory: 8192
net0: name=eth0,bridge=vmbr0,firewall=1,gw6=2001:19c0:1::1c01,hwaddr=72:43:48:E6:BF:3A,ip6=2001:19c0:1::1c03/120,type=veth
ostype: ubuntu
rootfs: local:250/vm-250-disk-0.raw,size=100G
swap: 8192
unprivileged: 1