> plus they don't seem to release security updates promptly.

They did announce they're going to do daily linux patches though, so that's atleast something https://www.phoronix.com/news/Fairphone-6-Linux

So Fairphone is NOT secure?

Fairphone is as insecure as most non-flagship Android phones. Make of that what you will.

GrapheneOS takes security very seriously. Your average desktop PC or laptop won't come close to their requirements. That makes GrapheneOS an excellent OS for people who want the security of iOS without the many downsides of Apple. Their patches reduce usability but make the phone more secure than Google's own, official Android build.

However, if you've ever used a Windows (or Linux) laptop, you've already experienced the kind of insecurity that GrapheneOS tries to prevent. No hardware encryption accelerators outside of the CPU, rarely any patches that roll out within a weak of announcement, firmware protection being basically nonexistent, no A/B updates, almost certainly no verified boot (even with Secure Boot enabled), and usually no firmware USB lockdown.

Interesting enough, GrapheneOS runs exclusively on google devices. This fact makes it obsolete for me. I don't trust google in anything, soft or hard ware.

Security is a policy-driven spectrum of considerations and solutions. GrapheneOS targets very specific threat models, which is not possible with Fairphone hardware/BSP. Whether it makes it not secure for your own use cases, it's up to you to decide.

Case in point: re-lockable bootloader requirement. Not everyone is a target for an evil maid types of physical attacks or possible state actor pressure. But when you actually need it, it's not negotiable.