Question with google assistant command to play with google 3rd party integration

Hi,

What I want to achieve:
use siri to open panasonic bluray UB820, turn on the tv and switch to correct hdmi input.

What’s done:
I’ve setup node-red + homeassistant, able to do everything except for turning on bluray player
I’ve setup google assistant relay, able to get response successfully,
I’ve setup Panasonic Blue-ray voice control in google assistant (which is a google 3rd party integration service https://assistant.google.com/services/a/uid/000000968c44d7b2), I can voice command bluray player successfully using iphone’s google assistant app

I have tried following below

  • the old Panasonic Blue-ray integration, not working
  • google assistant relay to execute command ‘ask Panasonic Blu-ray to turn on’, which can be successfully executed on iphone google assistant. but not working using google assistant relay, response is ‘ok, start broadcasting.’ or ‘sorry I cannot understand’
  • setup ssl on all my home network and integrated with official google assistant integration. but it can only let google control HA devices, which is not what I want.

I cannot find any other tech alternative to solve this now.

My guess is, google assistant relay need to have at least one google home server device in home network?
That’s why it’s responding ‘ok, start broadcasting’? Maybe it targets the action correctly but cannot find anything in network to help executing it? Maybe it’s a different way compared to iphone google assistant app?

Or maybe it just won’t work with google 3rd party integrations, too many layers?

I don’t have any google-home-server-ish device currently, Nest mini does not cost too much but i don’t want to waste money.

can anyone help testing my guessing?
can you execute complex google command thru google assistant relay without any google home server device in home network?