[deleted] I know that on OnePlus 8, resetting the phone via recovery mode is password protected (with the screen lock password)
That depends on Google Play Services having privileged access to the device.
I'm not aware that GrapheneOS is going to offer the ability to recover you profile if you forget your password like Google does on stock Android. Therefore, without the ability to factory reset from recovery mode, you'd have a bricked device if you ever forgot your PIN.
[deleted] This is crazy ! If I had secrets documents on GrapheneOS, literally everybody could delete them... Or if someone was angry against me he could delete my phone...
It's best practice to backup your data.