SS-Speedwagon Getting information from non-experts on social media sites like Quora isn't a good way to inform yourself. That particularly answer gets a few things wrong but isn't that bad. Quora and similar sites are usually far worse than that, especially Reddit. Searching for what you say you're searching is going to give you lots of misinformation from people who don't know what GrapheneOS provides and haven't used it.
For example, most sources falsely claim GrapheneOS provides less app compatibility despite it having much broader app compatibility and have false claims about performance, usability and other things. GrapheneOS and CalyxOS are much different kinds of projects. CalyxOS is very similar to LineageOS and heavily based on it. GrapheneOS is a hardened OS with substantial privacy and security improvements:
CalyxOS is not a hardened OS. It substantially reduces security. It recently went 2 months not shipping standard security patches and rolls back multiple parts of the security model. It does not try to preserve security and does not preserve the standard security. It's not far from LineageOS with different bundled apps and a few minor extra privacy features which don't all work properly such as their leaky toggles for network access they present as a firewall app.
Compatibility with Android apps on GrapheneOS is also much different. GrapheneOS provides our sandboxed Google Play compatibility layer:
Can run the vast majority of Play Store apps on GrapheneOS, but not CalyxOS with the problematic microG approach.
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. Talks about other alternate operating systems including DivestOS. Unlike most content, these are based on real experience and technical details.