I’m not sure what you mean about without sudo - if there’s a root account logging over isn’t more secure than SU or SUDO. At some point you trust someone with root access either by ssh key, password or sudo abilities.
Openbsd har a rather stellar security history, but there’s still root.
Also there’s still root on Android, so I don’t agree with your point of “Android fixed Linux”. You don’t need to elevate to install software, but the software you install can elevate (www.tomsguide.com/round-up/best-root-apps)
In what way is the need for privileges for system stuff like boot config solved without root?