It is not a question that can be answered with a yes or no answer.

Within Linux you have more secure and less secure distributions, for example the default security of an Arch Linux is crap because it has neither apparmor nor selinux and putting it is a pain in the ass, nor secure boot.

Nor does OpenBSD offer the same security as FreeBSD, OpenBSD being considered the most secure operating system in the world.

I could summarize it this way from more security to less security.

OpenBSD > FreeBSD > Debian > Fedora > Arch Linux

As handicap of the BSD is that they do not support secureboot, although FreeBSD is in process.