Installing your own build does wipe the device when you unlock the bootloader, yes, but updating it with a locked bootloader does not. It would be a one time transfer if you have official images already installed.
Your paths forward are a false dichotomy. These are not the only 2 options. You can simply update your build with the changes you want.
The randomness of an app is irrelevant and apps need to jump through significantly less loops to obtain root access without your input. And even if they didnt do that, and you permitted root instead, the app can lie about you revoking it later in either case.
This is blind ideology over safety and real ownership. Root is a hacky shortcut for proper functionality, and is not a prerequisite to ownership in the slightest.
Okay, so once I install grapheneOS, how do I update it with my own custom build while keeping my data intact?
> You dont have the ability to guarantee you have overridden anything. The integrity of the OS cannot be verified and anything with root can lie to you that it was revoked. It does not put power in your hands.
You haven't read anything of what I've written, it's incredible.
You're continuing to use the term "root" to mean granting full power to random apps.
I'm using the term "root" in Linux terminology.
It's not advisable to run random software as root, no matter what platform you are on.
But the OS' native file explorer and shell, in this case com.android.documentsui/com.android.files and adb, should allow the user to authorize themselves as root and read/write to any file.
Its not advisable to run anything as root, at all. Or expose access to it in any form.
You can make userdebug builds to access a form of root that doesnt undermine the entire security model, in ADB. Afaik this lets you access apps internal directories but is not recommended for production devices.