How to set the mDNS IP for Google Assistant local fulfillment?

I’m running Home Assistant in a Kubernetes cluster using the official Docker image. I want to avoid running it with host networking, so I’m running a mDNS on the node in reflector mode.

Now I’m trying to use the Google Assistant integration with local fulfilment. I followed the instructions, including the local fulfillment instructions, here: Google Assistant - Home Assistant

Using a mDNS discovery tool I can see a _home-assistant._tcp. entry, but the IP address is the internal Kubernetes IP, even though I’ve set an internal IP in the Home Assistant settings, which also shows up as “internal_url=http://my-local-ip:8123”.

I assume for local fulfillment to work, the actual IP address for _home-assistant._tcp. needs to be reachable by my Google Home devices? Is there any way to set the IP for this, similar to the advertise_ip option for other integrations?