Nie wirklich selbst im Einsatz getestet.

While what you use is your perogative, if you are looking at the LineageOS due to being concerned about security/privacy and that being a focus of your decision making, the following should be taken into account.

GrapheneOS and LineageOS are much different. GrapheneOS is a hardened OS with substantial privacy and security improvements:

https://grapheneos.org/features

LineageOS is not a hardened OS. It substantially reduces security. Then due to a focus on broad device compatibility, devices can either be behind or where they are no longer supported by an OEM completely outdated regards security patches.

Compatibility with Android apps on GrapheneOS is also much different. GrapheneOS provides our sandboxed Google Play compatibility layer:

https://grapheneos.org/usage#sandboxed-google-play

Can run the vast majority of Play Store apps on GrapheneOS, but not LineageOS if using the problematic microG approach instead of privileged GApps.

LineageOS always uses multiple Google services too while giving them privileged access even if users don't use microG. It would be wrong to imply they don't use Google services. microG is of course an implementation of Google services. GrapheneOS doesn't use Google services by default.

To clarify further they always use Google services even without microG. They use Google for connectivity checks, network time, attestation key provisioning, SUPL, DNS fallback, PSDS (Pixel 6 and 7), eSIM activation and more enabled by default.

https://privsec.dev/posts/android/choosing-your-android-based-operating-system/ is an article about privacy and security differences between alternative Android-based operating systems.

If you have any questions you know where I am, always happy to help. Take care.