There is an answer. /u/Myric277 has suggested a course of action that worked for me and others. I uninstalled the System App: Android TV Home. It rolls back any updates to the original settings. I then used the Google Play settings to turn off auto update for all apps.
The ads are gone, for now. Google ads are easily startled, but they'll soon be back, and in greater numbers.
Hi, Ben from 9to5Google here. Google told us this cannot be turned off.