I've used FreeBSD and OpenBSD. For around a year in 2013-ish, I daily drove OpenBSD until proprietary crapware I needed at the time mandated either a virtual machine or a Linux installation or a physical Windows installation, so I hopped back off. Those were comfy times. OpenBSD man pages are more or less what I aspire my writing to be: Clear, concise, yet readable. I still messed with OpenBSD occasionally and found several documentation issues, sent patches to tech@ until I got Theo'd on the mailing list and haven't been back since. I still check their code since more often than not, they have a reasonable idea (assuming you're like me and assume "reasonable idea" maps to "UNIX if the 90s never ended"). Unfortunately, they're very bone-headed with regards to their copyright policy (which I do respect) and with regards to how the world works (you can't really pull having no Bluetooth stack in 2023 unless you're doing a practical joke, but they stick with their ways).

FreeBSD is just Linux but several years later. The only innovations in recent times were taken from illumos/Solaris. Security posture seems practically absent for anything but directly exploitable issues; they took forever to put in ASLR, left the biased RC4 in arc4random(3), etc. Not a fan.