[summm]

Root doesn't mean you give root permissions to any dumb app. I implied proper permission management and authorization, of course.

Then it's just like a secure castle where the user can go into all of the rooms, to some with a special key. You don't have to go into those rooms, but you have the option to at any time. And, depending on the implementation, you may change the special room, but if you return after the next reboot, it will be reverted back.

Actually, the castle analogy goes further: Unfortunately, many seem to interpret "verified boot" and "most secure" as "protects the dumbest user from shooting themselves in the foot on purpose by locking them into that castle. That is exactly where the recent apple scandal is coming from: The user is subservient to the OS vendor, and the OS vendor can abuse the user as they please.

Security is very important. Why? In order to not be exploited by strangers (criminals, spys...) against my interests. If security enables exploitation against my interests (by whomever, be it the OS vendor, the movie industry, or the government), it is not the security I want. This one OS is different than all the other evil ones? That's what Apple said before...

[luca020400]

If you're rooted your security is way lower. Simple as that. Rooting can be used against you, it can lead to exploitation, and likely has been.

Note: you can have secure boot without root and using your own Android build, such as CalyxOS. Not rooting doesn't imply using the stock firmware, never has been.

[summm]

I honestly don't understand why it should be "Simple as that"? If you have the phone rooted, as long as you don't grant root to any application, why should it be less secure than if you hadn't rooted it? (assumed everything else the same, specifically the rom supporting verified boot with root) Then, by granting root permissions to apps, of course the attack surface gets larger, but this is a thing you control yourself.

Your note was always understood. Of course not rooting doesn't imply using the stock firmware. It however implies that you are submitting to a different master. Who may be different, and maybe a bit more lenient than Google/Samsung/whoever, but that other master will still enforce any dumb app's will against you.