GrapheneOS is the easy to install OS among any mobile platform. Everything is through a web UI, so you are very unlikely to brick your phone. You don’t need to type a single command. Also even if you brick a Pixel phone, it’s very easy to install stock Android build through Google with a similar installation process.
FSF does not get in the way of security. FSF believes source code should be publicly available in order to even assume the software is secure or private. In a perfect world that would be nice. But in the real world, proprietary blobs are required to make the hardware functional. As long as OEMs are removed about open sourcing the firmwares, both GrapheneOS and GNU are right in their own way.