I did a bit more playing with it and found that it worked with Google Assistant on my phone, but not our Google Home. Intriguing. Taking a closer look at the Google Home setup, I realized that it was set up using my wife's Google account. Sure ...
I was able to connect Telus Home Assistant in the Google Home app, but when I ask my Google Home to control the Optik box (change channels, for example) it says it's not there. I've just started playing with it so hopefully it's just user error.