upstage4186 If what you're saying is true then maybe I don't even need GrapheneOS at this point
Oh woah, slow down there a bit. I don't know how you jumped to the conclusion that what I said would in any way imply even in the slightest bit that GrapheneOS would have no benefit anymore - it did not imply this at all.
There is a huge privacy difference between privileged and sandboxed Play Services. On normal Stock OS where it is privileged it can access basically everything. On GrapheneOS it can only access what unprivileged apps can access (which is really not much) and then on top what you specifically grant it via permissions or actively share with it.
Google can only aggregate and send out data as telemetry it can access in the first place. It can access significantly less on GrapheneOS.
Also don't forget all the other security and privacy improvements that GrapheneOS has. They are in no way made irrelevant or obsolete by anything.
Especially if you have to use privacy-invasive apps, it's best to use them on GrapheneOS.
upstage4186 I assume Aurora is leaking certain identifiers?
Aurora Store still doesn't matter here. You are installing apps, they run on your device and can get information about the environment they are in.
upstage4186 Eek, do you know how exactly they go about doing this?
There are some side channels how an app could guess that it's on the same device or profile, potentially even after a reinstall or across profiles. As a simple example, if two apps from two different profiles see the exact same battery percentage over a prolonged period of time and also get shut down at the same time, it can be likely assumed that they are on the same device. But apps could use a combination of multiple side channel factors to get a more accurate estimate. This is not really something that can ever be fully prevented, but also not really that big of an issue in reality.
Apps bundling Google libraries can also talk to each other (if installed on the same profile) and correlate that they are all installed on the same profile.
upstage4186 I expect that I can't remain 100% anonymous, but I thought using GrapheneOS without a Google account or Play Services would give me some level of privacy. 😮💨
It does give you very good privacy. But it is not about if you have Play Services or not, but about you using the Play ecosystem at all. Avoiding Play Services but still installing Play Store apps anyways just only from other sources (like Aurora Store) doesn't magically and suddenly avoid Google and its tracking. Play Services itself is not the part that matters here.
If you rely on apps from the Play Store, get them from the official Google Play Store with sandboxed Play Services.
This is the best way to go about it and gives you a very good level of privacy, way higher than on Stock OS with privileged Play Services and not that much worse than not using the Play ecosystem at all, depending on how you use it. You can still minimize the data you give Google, use an anonymous Account, etc.
In any way, your best bet is GrapheneOS.