The locked bootloader is having a lock at all. Without that, anyone can enter at any time.
In reality, home door locks are merely suggestions, they’re trivially picked or broken open, windows can be entered through. But if you DID have a secure building, you wouldn’t want any of the security systems to be replaced.
You get full access to operate in a secure building once you’ve used the key/biometrics/passwords/interrogation. You don’t have access to replace the locks with tinkertoy homebrew shit, because we know that’s not as competent.
If you write to a text (as opposed to binary) stream, \n produces \n or \r\n (or \r if old enough) depending on platform just fine.
Nobody should be using C++ anyway, but plenty of languages have silly system newline constants, which do nothing useful.