Thankyou for considering GrapheneOS, appreciate that.
While what people use is their prerogative, if you are looking at the OSes due to being concerned about security/privacy and that being a focus of your decision making as well as app compatibility/ease of use and installaton, the following should be taken into account.
GrapheneOS and CalyxOS/LineageOS are much different. GrapheneOS is a hardened OS with substantial privacy and security improvements:
https://grapheneos.org/features
CalyxOS/LineageOS are not hardened OS, substantially reduces security. CalyxOS recently went 2 months not shipping standard 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 CalyxOS/LineageOS with the problematic microG approach.
GrapheneOS also doesn't require any CLI (Command Line Interface) knpwledge and helps protect users from bricking their devices by using our simple click through web installer process:
https://grapheneos.org/install/web
CalyxOS is closer to LineageOS they both share the same issue above and they both always use 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 (LineageOS only), PSDS (Pixel 6 and 7), eSIM activation and more enabled by default.
https://blog.privacyguides.org/2022/04/21/grapheneos-or-calyxos/ is a 3rd party article explaining some of the substantial differences between GrapheneOS and CalyxOS. It's a common misconception that they're similar. CalyxOS is far more similar to LineageOS than GrapheneOS. There are many other alternate OSes available.
https://privsec.dev/posts/android/choosing-your-android-based-operating-system/ is another article about privacy and security differences between alternative Android-based operating systems.
If you have any questions/feedback though you know where I am, always happy to hear. Take care.