Can you in principle sue people buying these ads for trademark infringement? (I realize in practice the answer is that it's not worth the game of whack-a-mole.)
Look at the screenshot in this post. All four of the ads at the top of the search results include the trademarked name "Midjourney" in the title of the ad.
This is more like putting up a giant sign outside of your Honda dealership saying "Best deals on new VWs!" but when you pull in they don't sell VWs, they sell their own competing products.