Anonymous What was mentioned above, and what you're quoting doesn't really make a lot of sense.
A sandboxed app only has access to what you allow it to via user-controlled permissions. The permissions which don't require user consent don't grant access to user data as a rule.
Of course, GrapheneOS significantly strengthens the sandbox in multiple ways, so that is even more true there.
It is unclear to me what people are trying to say above, but that's not quite how things work.
Permissions for regular apps are indeed split between permissions classified as "dangerous" (think contacts, storage permissions) and "normal" permissions (think permissions that have to do with battery optimization and similar other things). The normal permissions do not require user consent precisely because it doesn't grant access to user data.
I think that answers the question posed in the OP (which as far as I can understand is "should I be concerned about declared normal permissions of an app that I cannot toggle myself?" for which the answer is no, as those permissions aren't user-facing by design and typically have to do with under the hood application optimizations like when the app runs, when it doesn't, whether it can ask for unrestricted battery usage etc.)
As such, I will be locking this thread as it is quite an old one. If there are follow-up questions about permissions that extend beyond the scope of a specific app, it likely makes sense for a new thread to be created, so please feel free to do so.