I don't know enough about this level of IT to rebut this.

I use Linux for my router now because my server is NixOS, so I was able to consolidate my router into my server and turn off a machine (and thus save a little power), and I have so thoroughly drunk the Kool-aid for NixOS that I kind of want to put it everywhere. I run the latest kernel and I update daily, so I think most bugfixes (and hopefully security updates) will manifest quick enough.