Those are Java package names. Android is written mostly in Java/Kotlin. Java being Java, the recommendation for package names is to use reverse domain name syntax to uniquely identify your stuff. So most of Android's core is under the com.android.*
namespace, and Google's extra stuff usually under com.google.android
or something like that.
Android is also extremely modular, so a lot of the system is also just regular Android apps, including settings. That's why you can see say, "Android Easter Egg" which is the hidden system app that gets launched when you tap the version number in settings a few times.
If all you installed is GrapheneOS and Google Apps, I wouldn't worry about malware. Google's stuff might be spyware but that's up to you to judge, but nothing that wouldn't run anyway on your stock OS.