FreeBSD is throughput oriented in a way that OpenBSD certainly isn't, and I don't think NetBSD is either (although, I haven't really looked, I feel like NetBSD competes on portability and doesn't spend a lot of time making sure networking throughput is high).
All of the BSDs tend to have a lot less churn, for better and worse; so IMHO, they make a nicer platform to integrate on.
If you want a high profile example, look at what Netflix CDN does.
Could you do that work with Linux? Probably --- but nobody who does is talking about it as much.
This kind of high throughput service has been a FreeBSD niche since forever too. Walnut Creek CDROM, Inc ran what was reportedly the world's busiest ftp site, ftp.cdrom.com on FreeBSD in the early days of the internet.
Yahoo ran on FreeBSD (I worked there 2004-2011) WhatsApp ran on FreeBSD (I worked there 2011-2019) Both were leaving FreeBSD when I left, but sadly, I didn't leave to work somewhere else with FreeBSD :p
Also checkout DragonflyBSD. They, at least at one time, where gunning for the HPC use case.I don't keep up with it enough to know the current state today, to know if they are still hard charging in that direction since they forked from FreeBSD years and years ago.
All of the BSDs tend to have a lot less churn, for better and worse; so IMHO, they make a nicer platform to integrate on.