The ads are in the app store and about apps. Googles ads are all over the web and they’ve embedded trackers in every website that call home and tell google what you’re up to. Most android apps also have Google libraries in them that track you. Chrome monitors your off Google activity. Gmail extracts purchase receipts from online shopping and monitors your spending to serve ads. Meanwhile, Apple forced app developers to ask for permission to track users and pissed off the entire tech industry. The two are not the same from a user privacy perspective.