For anyone interested, here is benchs from late 2018, comparing Fedora and FreeBSD performance: https://matteocroce.medium.com/linux-and-freebsd-networking-...
I've been doing this for stuff like SMTPE authority servers and ntpd and things that absolutely cannot go down, for over a decade.
There are also VirtIO drivers involved, and according to the article, they had effect too.