It is not possible to turn the Google Assistant feature off on the headphones, but if you turn off GA on your phone, the headphones won't trigger. On the Everest GA models, the Google Assistant feature is in fact than an extension of your phone, so once you connect to your phone via BT, when you touch the right ear pod, it commands your phone to open the "Hey Google" command.
The only way to stop that from happening is to change the Google settings on your phone to deactivate Google Voice Match, or deactivate Google Assistant entirely.