The way I used to open Google Assistant’s settings page is by launching the app and then tapping the briefcase-in-a-blue-circle icon and then tapping Settings from the menu. Recently, I figured out an easier way to open settings.
Just say: Show me settings to the Assistant.
This commands takes you directly into Google Assistant’s Settings page. The first time I tried this, I thought it will open phone’s settings app. Luckily, it opened Google Assistant’s own Settings page. Next, I tried Show me phone’s settings, but that did not work. May be there is a different command to launch phone’s settings.
So, the next time you want to access Google Assistant’s settings to tweak something, just say “Show me settings”.