It definitely helps. In GrapheneOS, Google Play Services can be installed, but it is sandboxed and doesn't even have network access unless you allow it.
It solves so much more though, like through scoping you can give an app access to your contacts, or just specific contacts; to the app, those specific contacts are the only contacts that exist on your phone.
They have Google services but through a third party wrapper called MicroG, which keeps it sandboxed to a degree that you can keep it from doing system-level actions like this
edit: not microG, as evidenced by the strikethrough I put in very soon after receiving the first of several replies clarifying the situation. I would encourage you to read one of them before adding your own. <3
Gos doesnt use MicroG. MicroG is a foss implementation of googles APIs, with very ways to be tracked, and the ability to turn those components off.
Graphene says "you get nothing or you get these closed source black boxes we sandboxed".
Install AirGuard, if you're concerned about people stalking you. Install an icon pack and/or switch to a different homescreen app? I prefer that Graphene gives users freedom to setup their phone however they want.