Ads in vehicles are a sure thing. Also a sure thing you'll be able to pay a little extra to turn them off, which is basically just the full price of the trip unsubsidized by ads.

It'll be up to you, just like whether you want your Netflix cheaper with ads, or more expensive but without.

I see that choice as a good thing.

The rest of your suggestions are incredibly unlikely. Google doesn't even scan your Gmail anymore, you think they're going to create a privacy scandal by listening to your conversations? And they certainly don't sell your Maps timeline which is far more valuable than just a few car trips, so why on earth would they do that with Waymo? Nor does Google Maps offer to send you to Burger King when you hit directions for McDonald's. And taking a longer route that wastes time, battery and money, on the chance you'll be looking out the window to see a billboard rather than looking at your phone, doesn't make sense at all.