When I set up the Google Home speaker to control smart home devices, I could easily find the Home Control menu item in the Home app. It comes with a few more items like Things to Ask, Music, Shopping List, and More Settings. However, all of those items disappeared after I stopped using the Google Home speaker.
I expected I could still use the Google Assistant to control lighting and other smart devices in my house, however, I couldn’t see the Home Control option anymore. Fortunately, it is actually still there and I find out how to continue using Google Assistant on my Android phone. Check out the video below to see where it is hidden.
Update: It seems like Google is trying to hide the Home Control settings and make the feature available for Google Home speaker users only. However, you still can find the settings as shown below.
Following is an older tutorial:
You will need to call Google by saying “OK Google” or touch and hold the Home button. Then tap on the 3-dot icon on the top right corner, open Settings. You can see the Home Control option right there. Now, you can add a new device or assign it to a new room.
Let me know if the guide resolves your issue.