To be honest, as an IT professional you should have basic knowledge about firewalls. nft/nftables is a big improvement in firewall usability for Linux, I also know many homelab people using OPNSense or even DD-WRT for that job. I prefer plain Linux (distro of your choice, I don't judge) and nft.
TL;DR
One should know firewall fundamentals, nft/nftables as successor of iptables is very convenient to use, a single config document instead of interactiving with 100 cli commands which have to be in a specific order.