GrapheneOS provides major privacy enhancements including Contact Scopes, Storage Scopes, Sensors toggle, per-connection Wi-Fi privacy via per-connection DHCP state + MAC randomization and far more. It's a privacy project and privacy depends on security so it heavily focuses on protecting against exploitation of privacy and security vulnerabilities too. Privacy and security are not separate things from each other but rather closely tied together and our work is on both for the sake of improving privacy. Our only reason to work on security features is protecting privacy.

I disagree, privacy is an essential part of security, if there's no privacy, then there's no security.

That's also why I don't keep anything important on my phone as I don't trust what's going on there despite having all the secure features that you would want.