Please support your claim about (networking) performance of BSD-based systems and Linux with some source(s). It surprised me. Thank you.

Anecdotal, but I was never able to get FreeBSD (TrueNAS CORE, OpnSense) to get anywhere near 10 Gbps. Using Mellanox or Intel NICs. The Linux equivalents (TrueNAS SCALE, OpenWrt) handled it fine on the same hardware.