Actually LineageOS has less usability due to AOSP bugs, no GMS, unlocked boot loader, etc. The weak security is cost of wide support.
GrapheneOS has even less usability on my Oneplus 7T Pro, in fact it has none
i'm fine with that "less security" as my threat model does not include crossing the US border.
Could you explain how the ability to unlock a bootloader makes a device less usable?