I want to challenge your position.

Sometimes linux is considered not secure for the components it includes (systemd, gnu stack...) and the fact that it doesnt enforce security practices by default.

But why not using linux with good componemts, like:

/hardened-customized-linux/openrc/mus-libc/a minimal WM/pure ALSA/unix-stile-utilities IOMMU enabled, spectre and other cpu mitigations active in kernel, MAC with Selinux and so on.

Linux is a standard. Probably most common distros are bad, but you can build the Os you want and you have a lot of options to do that.

Bsd are linux but 15 years ago. But you can build your linux based os like its 15 years ago, using the best options and end with a better os, secure for your needs. Bsds are shitcoin, mac is just trash.