Trying to get Matter to work with Synology. How to enable IPv6 for host on Container Manager?

Hi. I have Home Assistant installed in a docker container on my Synology but I need it to work with Matter-Server which I have also installed. It turns out that matter devices only communicate through IPv6 and when I look at my container manager I see that for host, the IPv6 is disabled.

IPv6 is enabled on the Synology network interface so this is a docker/container manager set up issue.

Is there a guide for how to do this with container manager anywhere? I’ve see this guide for native docker Enable IPv6 support | Docker Docs but I am not sure now it relates to the Synology container manager version or even where the container manager files are located.

Help!