I can only comment on OpenBSD. It’s a minimal unix system. I like the minimalism. OpenBSD is mainly a router/server/firewall system but you can use OpenBSD on a desktop. If your hardware is supported everything works out of the box. Firefox/Chromium have pledge/unveil security which prevent them from accessing your file system. Something like apparmor but works put of the box. However it’s not designed as a desktop system (installing a browser introduces many security risks). They have some additional security features like encrypted swap and others. In terms of security, the OpenBSD kernel is a lot smaller than the linux kernel. Can’t have holes in code that doesn’t exist. All together it’s just a minimal small unix system.

If you want to use it on the desktop, you can use it for basic surfing or 90s video games. I’m using it for fun mainly. There is no jails / docker / virtualbox so I don’t use it for coding.

OpenBSD isn’t really a desktop OS, desktop users typically use FreeBSD because there are many more packages. FreeBSD is a completely different OS.