Having been on the other side of the picture, I can tell you - those who have access to your data don't have time to look at it longer than it takes to fix what they're fixing, and those who have time couldn't buy access with the treasury.
No one's interested in your contacts or pictures. (If you were stupid enough to keep plans to assassinate the President in a text file, some automated process might find it. But if you have the recipe to win the next national bake-off, no one's going to know.) Google keeps data on how many suggestions from G-Board are accepted - the number of them, not who's accepting them. That's the kind of data they're "spying on".
They may "keep track" of which ones are are selected, but only as training to an AI system. Remember, Google is big into AI. They want your next text app to fill in the whole sentence as you start to type the first word. And feeding petabytes of data to it is how you train an AI system. It's hoe Google Assistant was trained. But keep a record of who called what and said which? That's data they'll never use, so they'd never keep it. (Even Google has limits on data storage - they can't buy petabyte drives.)