What data can an app collect from a phone running regular Android vs GrapheneOS?

There are goverment apps I need to install on my phone. I heard that GrapheneOS is ideal for that, since GrapheneOS user profiles are reliably isolated from each other, I can install all the government apps in a separate user profile, so those apps cannot communicate with or snoop on my other apps. But if I don’t use GrapheneOS, what can those apps do on my regular Android phones? What data can an app collect from a phone running regular Android vs GrapheneOS? What’s the difference?